Support for Arch Linux

`ArchDockerContext` adds support for isolated development environments based on Arch Linux.

Enable installation of PHP in Ubuntu 18.04

Unfortunately, the implicit installation of tzdata causes the Docker image build process to block, even when employing DEBIAN_FRONTEND=noninteractive. Therefore I'm forced to manually install tzdata on every build in order to allow installation of PHP in Ubuntu 18.04 😞

Support for Debian

Tested with Wheezy, Jessie and Stretch.

Making mini-cross installable through npm

Cross distribution package installation is still an unsolved problem.
While where are many solutions like flatpack, non gained enough traction
to yet.

Nevertheless, since mini-cross appeals to developers, there's a high
likeliness npm is already installed. Therefore I'm making mini-cross
installable through npm

```
npm install -g mini-cross
```

This will install the `mc` binary into your system path. Multiple
versions can be chosen from on the command line e.g.

```
npm install -g mini-cross@0.11.1
```

Since docker already requires `linux-x86_64` the node package only
includes that target.

Added publish instruction

It's now possible to add port forwardings using the `publish` instruction, e.g.:

````yaml
---
base: ubuntu:16.04
install:
 - apache2
publish:
 - 8080:80
---
````

All current [publication formats](https://docs.docker.com/engine/reference/run/#expose-incoming-ports) of docker are supported.

Test all supported operating systems

Previously only one Fedora and one Ubuntu version was tested. Now the smoke test is executed on all supported operating system versions:

 * Fedora 24
 * Fedora 25
 * Fedora Rawhide
 * Ubuntu 14.04
 * Ubuntu 16.04
 * Ubuntu 16.10
 * Ubuntu 17.04

Application bundle using Traveling Ruby

For ease of deployment, mini-cross now utilizes [Traveling Ruby](https://github.com/phusion/traveling-ruby) to provide a bundled application. Therefore it's no longer necessary to have Ruby and other Gems installed on the host system to use mini-cross.

YAML configuration support

With the implementation of YAML configuration support in `YamlConfigurationParser`, the initial feature set for mini-cross is completed. It is now possible to specify multiple development environments on a per project base.

Missing features, to be added in following releases:

 * Support for including other configuration files (e.g. having one shared configuration adding dependencies)
 * Support for more base systems (currently only testet for modern Ubuntu and Fedora distributions)