Merge pull request #784 from iHiD/readme_1

Two small improvements to the README
Add test coverage for double braces in sanitisation
Merge pull request #783 from iHiD/fix_469

Add test coverage for double braces in sanitisation
Fix the build after #783 broke it
Merge pull request #785 from iHiD/fix_the_build_after_783

Fix the build after #783 broke it
Fixes inclusion check for viewing teams page
Added tests for team routes
Merge pull request #786 from Tonkpils/fix-team-check

Fixes inclusion check for viewing teams page
Use persistent sessions. Fixes #653.
Make cookies valid for all paths
Avoid extracting mentions when comment is empty. Fixes #788.
Restrict access to future exercises (teams). Fixes #789.
Delete comments. Fixes #645
Fix edit nit endpoint
<strike>Whitesnake</strike> Whitespace
Allow creator to add/remove team members
Allow users to leave their team
Merge pull request #792 from Tonkpils/edit-team

Edit team
Add test for delete comment endpoint
Added airbrake