Update README.md

Update README.md

Updating to master

Updating documentation for news and urvey modules
Add documentation of mail, news, notification and survey modules.
Little code correction in my news module.

Little mistake in my markdown

Add missing methods in doc

Little mistake corrected

Little mistakes (again)

A little precision in explanations

Another mistake

Little mistake fixed

Errors fixed

Mistake fixed

Error fix

Fix build errors
Fix build error
Merge pull request #156 from GuillaumeGomez/master

Documentation update