Added a Composer file with license

With this commit we add the composer.json and lock file together
with a license file indicating that this project is under the
MIT license (discussed with @akrabat to be sure).

In addition to the above I have prevented the .git folder in the
vendor folder from being committed.

The vendor folder itself will be submitted in a separate commit
to make it easier for a code reviewer to see which changes are
the onces actually needing a review.
Replace all vendors with composer loaded vendors

The vendors folder was manually maintained and with the previous
commit we added support for composer to maintain the vendors for
this project.

With this commit we update the vendor folder to contain all the
generated dependencies by composer so that the correct versions
are deployed.
Rewire application to use composer

The composer no longer requires on custom autoloaders. Composer
takes care of all these necessities.

In this commit I have removed all existing autoloading code and
added the autoloading of composer.
Merge branch 'master' of github.com:joindin/joindin-web2 into insert-composer

Conflicts:
	.gitignore
Merge branch 'insert-composer' of github.com:mvriel/joindin-web2 into pr117
Merge branch 'pr117'