Add a composer.json file to the framework

Add a composer manifest to the framework. This will let people manage installation and updates of dependencies very efficiently while also keeping the size and complexity of the framework itself small.

The vendor directory and composer.lock files will be ignored by git.
Replace the old autoloader with Composer's
Remove the Core directory from MicroMVC

Core is now Micro and is provided in the vendor directory by composer.
Replace \Core with \Micro
Merge pull request #36 from johnpbloch/Micro

Composer Support for MicroMVC