* add notification interface and refactor UI notifications

* add missing methods on notification interface and notifiy only issue status really changed

* implement NotifyPullRequestReview for ui notification

* prevent pull request to be merged when PR is a WIP

* add tests

* add helper to prepend WIP: in PR title

* move default wip prefixes into settings

* use configurable WIP prefixes in javascript and default to first one in templates

* add documentation

* add unit test on pull model

Signed-off-by: Julien Tant <julien@craftyx.fr>

* Started adding deadline to ui

* Implemented basic issue due date managing

* Improved UI for due date managing

* Added at least write access to the repo in order to modify issue due dates

* Ui improvements

* Added issue comments creation when adding/modifying/removing a due date

* Show due date in issue list

* Added api support for issue due dates

* Fixed lint suggestions

* Added deadline to sdk

* Updated css

* Added support for adding/modifiying deadlines for pull requests via api

* Fixed comments not created when updating or removing a deadline

* update sdk (will do properly once go-gitea/go-sdk#103 is merged)

* enhanced updateIssueDeadline

* Removed unnessecary Issue.DeadlineString

* UI improvements

* Small improvments to comment creation
+ ui & validation improvements

* Check if an issue is overdue is now a seperate function

* Updated go-sdk with govendor as it was merged

* Simplified isOverdue method

* removed unessecary deadline to 0 set

* Update swagger definitions

* Added missing return

* Added an explanary comment

* Improved updateIssueDeadline method so it'll only update `deadline_unix`

* Small changes and improvements
* no need to explicitly load the issue when updating a deadline, just use whats already there
* small optimisations

* Added check if a deadline was modified before updating it

* Moved comment creating logic into its own function

* Code cleanup for creating deadline comment

* locale improvement

* When modifying a deadline, the old deadline is saved with the comment

* small improvments to xorm session handling when updating an issue deadline
+ style nitpicks

* style nitpicks

* Moved checking for if the user has write acces to middleware

* Replace all ctx.Handle with ctx.ServerError or ctx.NotFound

* Change Handle(403) to NotFound, avoid using macaron's NotFound

* Pull request options migration and UI in settings

* Add ignore whitespace functionality

* Fix settings if pull requests are disabled

* Fix migration transaction

* Merge with Rebase functionality

* UI changes and related functionality for pull request merging button

* Implement squash functionality

* Fix rebase merging

* Fix pull request merge tests

* Add squash and rebase tests

* Fix API method to reuse default message functions

* Some refactoring and small fixes

* Remove more hardcoded values from tests

* Remove unneeded check from API method

* Fix variable name and comment typo

* Fix reset commit count after PR merge

* Update swagger documentation

Add docs for missing endpoints
Add documentation for request parameters
Make parameter naming consistent
Fix response documentation

* Restore delete comments

* Fix ignored errors in API route