Merge pull request #72 from claroline/refactoring-for-unit-tests-stefk

Refactoring for unit tests stefk
Changed wrong method names
Added hamcrest to dev dependencies
Added form factory
Added message repository tests and alternative repo test case
Added message controller tests
Added generic repository tests
Added authenticated user converter tests
Added multiple ids converter tests
Added a missing assertion
Added strict id converter test
Added exception codes to avoid false positives
Added missing doc blocks
Removed empty repositories