TypeTestCase

Hey. I prepared a `TypeTestCase` class with support a MopaBootstrapBundle form extensions. It will allow users to write a unit tests for a forms which uses MopaBootstrap form types.
I think having the conf available would make it easier, and tests can be written ob a per project basis too.
can you add an example test using this, to sandboixbundle and a new doc describing the purpuse please!
this is awesome!