Topics/composer

Went all in with composer.

The workflow to set this up, changes like so:

 * get a `composer.phar`
 * run `./composer.phar install`

I also did the following:

 1. Add the `composer.lock` to version control, this ensures whatever is required is installed.
 2. Extended `composer.json` to (hopefully) list all dependencies, add name, description and a license.
 3. Made phpUnit a _development dependencies_ and adjusted the `Makefile` to use it.
 4. Updated travis-ci configuration to install dependencies.


Let me know what you think. As far as composer is concerned I am done. But I'd have a couple more things which I'd like to do. ;-)