chore: add noasm for build on armv6 (gorgonia#321)

init of the encoding/dot package (gorgonia#309)

* feat: dot representation of a graph as an external package

* feat(encoding): a grouper is an object that can hold several groups

* feat: first round of a an encoding package

* chore: the encoding package is now internal

* fix: withGroup is unexported (by now).

the function is using an internal package. It is useless to export it by
now. This may change when the encoding package is stable enough

* fix(groups): a node is assumed to be in the ExprGraph group

* fix(groups): node is a Grouper; subgraphs are generated

* chore: all the nodes generated in the Conv2d are part of a group

* feat(subgraphs): first attempt to group nodes of the same operator

* fix: escape the html name and substitute the curly braces

* feat: generate the subgraph in a coral color

* wip: a bunch of improvements

* chore: add the grouping oprations for maxpool and rectify

* chore: prepare the inceptions of graph by adding a "IsPrimary" flag

V0.9.0 working 2 (gorgonia#227)

* Added Issue 217 to known issues
Renamed the ConstDeriv test to 182

* Added Reset() to BatchNormOp to conform to the same interface as the native version woul

* Clean up, and plugged some leaks

* Fixed a slight issue with the compilation. DoWork() is emitted before a linalg op now

* [fix] The test for Reshape Operator was incorrect

* Temporarily commented away the tests for gorgonia#217

* Added error message for VM Genera

* Added go1.11 to travis
Fixed CUDA Conv backprop shape error

* [fix] Using NewOrderedNodes as an implementation of gonum.Nodes

* Fixed the tests to use the new gonum interface

* Fixed an error in the error.warpf call

* [fix] Back to the idea that graph options should not be exported

* [fix] More idiomatic way to handle error msg

* Merged from v0.9.2-working2

* New stuff? I don't know when I did this

* Fixes gorgonia#257 I think

* Renamed examples/stacked autoencoder to examples/stacked_autoencoder

* Added tests. Added better error support for LISPMachine. Removed sanity check for now because there are some weird things wrt dimensions in dual values

* Updated with 237fix
There seems to be a problem with the concurrent training example, so it has been commented out for now

The `sanity()` method of the dual values have been temporarily suspended. Turns out lispMachines don't play well when there are differently shaped (but legal) derivations.

V0.9.0 (gorgonia#195)

Ongoing notes:

* **CUDA**: Better CUDA support (IN PROGRESS)
    * ~ColMajor used by default if engine is CUDA.~ (ColMajor is supported, but defaults to using RowMajor for all the major cuBLAS versions. Careful reasoning of the parameters obviates the need for ColMajor by  default, which causes more headaches. It is still supported)
    * Transposition will be automatically done when performing transports back to CPU.
    * cudnn operations supported (IN PROGRESS) (note: these are the ones I use more often hence gets bigger attention):
        * [x] Conv2d
        * [x] Dropout
        * [x] Maxpool2d 
        * [x] BatchNorm
        * [x] Rectify
    * Other CUDA related optimizations
        *  [x] full cuBLAS support
* **New Ops**:
    * BatchNorm 
    * InvSqrt
    * CUDA enabled ops in `ops/nn` (preview for how things will start to look in v0.10.0)
* **New Features**:
    * Limited shape inference.  Working towards a calculus for shapes (first raised in gorgonia#96 and gorgonia#97).
* **Optimizations**:
    * Optimizations of basic ops to use engine functions if available, otherwise, fall back to using `Apply`, which adds a penalty from repeatedly calling functions.
    * Faster VMs (1 of 2 VMs): ~greedy goroutines grabs gigs from a priority queue. This causes faster execution of  code in general.~ (this is moved to a future version of 0.9.xx):
```
benchmark                           old ns/op      new ns/op      delta
BenchmarkTapeMachineExecution-8     3129074510     2695304022     -13.86%

benchmark                           old allocs     new allocs     delta
BenchmarkTapeMachineExecution-8     25745          25122          -2.42%

benchmark                           old bytes      new bytes      delta
BenchmarkTapeMachineExecution-8     4804578705     4803784111     -0.02%
````
* **Code generation**: some exported API is now auto generated
* **New Solver** : @ynqa added the Momentum solver.
* **Breaking API**: `Solver` now take a slice of `ValueGrad` instead of `Nodes`. `ValueGrad` is an interface, of which a `*Node` fulfils. An additional utility function `NodesToValueGrads` has been added to aid with refactoring.  This was done for two reasons:
    * ~The support for BatchNorm operation, which is a verily impure and highly stateful function. The BatchNorm Op has internal states that need to have their gradients updated as well. But the internal state of BatchNorm isn't really part of  the expression graph, and really it shouldn't be.~ Turns out there was a better API for `BatchNorm`. 
    * In the next version,  v0.10.0. We aim to  do [better package organization](gorgonia#91) for managability.  With this API breaking change, the solver now is less dependent on the other parts of Gorgonia and can be easily separated.
* **Breaking Semantics**: A `gorgonia.VM` now implements `io.Closer`. It should be treated as a resource as well as a computation device - the VM must be `Close()`d in order for the resources acquired by the VM to actually be released. Turns out, automatic resource management is too difficult. Who'd thunk that?

Merge pull request gorgonia#202 from trigun117/master

Сorrected typos, fixed ineffassign, gofmt, go_vet

Merge pull request gorgonia#200 from gorgonia/variousbugfixes

Fixed a tiny bug in UnbindNonInputs.

Merge pull request gorgonia#192 from siquus/newSolversAndTests

New Barzilai-Borwein solver and solver tests

Merge pull request gorgonia#190 from gorgonia/189fix

Updated convnet example

Merge pull request gorgonia#179 from bradleyjkemp/patch-1

Fix table formatting

fixed travis to allow failures in go tip