Added support for java.util.Date on BodyParserEnginePost through SwissKnife class.

Added some tests on BodyParserEnginePostTest as well to make sure everything is OK.
Added information about date parsing on docs.
Added whitespaces as requested by @raphaelbauer.
Fixed wrong placement of functionality on the changelog.
Merge branch 'feature/date-parsing-form-post' of github.com:pedro-stanaka/ninja into pedro-stanaka-feature/date-parsing-form-post

Conflicts:
	ninja-core/src/site/markdown/developer/changelog.md
Merge branch 'pedro-stanaka-feature/date-parsing-form-post' into develop