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.
I did think about that.  It's very easy to not do that.  However, we will need to make the test case not error out because of that.  If that's OK with everyone, I will remove that logic.  Thanks.