Added SwitchCaseFixer - first draft.

This is to fix #776.  Please refer to original PR - https://github.com/fabpot/PHP-CS-Fixer/pull/2 for a bit more details.
Oh right, I was going to ask whether you want the test to just check the return to be -26 or compare that to the return of ```getPriority()``` from ```BracersFixers```.