Minor docs updates

Several bug fixes and improvements to CLI experience.

**added**

- as of v0.7.0, we will begin using the [keep-a-changelog][] format for release history
- adds support user-defined templates
- adds support for `app.home()`, which resolves to `~/` or the user-defined `options.homedir`. This directory is used to determine the base directory for user-defined templates.
- adds support for [common-config](https://github.com/jonschlinkert/common-config). Exposed on the `app.common` object (e.g. `app.common.set()` etc)
- adds experimental support for a `home` updater. If an `updatefile.js` exists in the `~/update` directory (this will be customizable, but it's not yet), this file will be loaded and `.use()`d as a plugin before other updaters are loaded. You can use this to set options, add defaults, etc. But you can also run it explictly via commandline with the `update home` command.

**fixed**

- fixes `app.cwd` so that it's updated when `app.options.dest` (`--dest`) is set
- ensure args are parsed consistently

v0.5.0 release

Adds assemble-core, assemble-loader. See changelog for more details.