Add Post & Comment POST/PUT/DELETE API methods

Fix feedbacks + add unit tests

Add some fixes

Fix POST and PUT methods to use form types instead of serialization

Remove non-used annotation

Fix feedbacks

Fix post controller method name

Fix APIs to use SerializationType

Remove post form type and add a check for deletion result
Fix exception typos
Merge pull request #178 from eko/api

Add Post & Comment POST/PUT/DELETE API methods
Merge pull request #181 from eko/fix

Fix exception typos
Merge branch 'sonata-project/master'