nitdoc: Added best way to check authentification

Adding a function to check if credentials informed are correct, if they
are or not a message is displaying to inform us.

Signed-off-by: Stefan Lage <lagestfan@gmail.com>
nitdoc: Added some field to github form

Adding a title field to its form, and a field to inform about which
the repository we entered when we sign in.

Signed-off-by: Stefan Lage <lagestfan@gmail.com>
nitdoc: Set all data type to JSON in Ajax queries

Change data type to JSON because there was somes troubles in commit
process

Signed-off-by: Stefan Lage <lagestfan@gmail.com>
nitdoc: Added Signed-Off management

Adding a Signed-Off field in the 'Sign In' form which allow to
'generate' its own signed-off for commits.
Addign a checkbox in commit form to obliged the customer to sign his
commit

Signed-off-by: Stefan Lage <lagestfan@gmail.com>
nitdoc: Inform if a comment was already modify

Adding a function in 'edit mode' which inform if the comment the
customer if the function which he is editing was already modify, it
allow to show this update to compare it with the original comment

Signed-off-by: Stefan Lage <lagestfan@gmail.com>
nitdoc: Fix bug: problem when getting function information

There was a 'bug' when we tried to commit, we didn't get the right
informations about the function which was editing, we get somes chars
which causes somes troubles in commit query. Because of the
adding of a tag in the last commit.

Signed-off-by: Stefan Lage <lagestfan@gmail.com>