Fix user mention bug when parsing markdown documents

This commit does a lot of the work of refactoring the access table in a table with id's instead of strings.

The result does compile, but has not been tested. It may eat your kittens.

fix highlighting css for del code

new lines highlighting format

Referencing issues from commit messages is now possible.

fix lines highlighting at diff view

fix error at admin/config

- templates/user/settings: fix email panel nav highlight

fix settings/email html&css

Fix #819 by fetching the repository from db before updating

Code-wise: the fixing-part of the code now doesn't reference the issue any more, because this is done by the referencing-part of the code, which is called just before.

Fixes #462, #668, #732.

add a function to rewrite all public keys on admin request

Add Miguel de la Cruz as a translator

correction: updated docker link

README: remove duplicated travis badge