* add google+

* sort signin oauth2 providers based on the name so order is always the same

* update auth tip for google+

* add gitlab provider

* add bitbucket provider (and some go fmt)

* add twitter provider

* add facebook provider

* add dropbox provider

* add openid connect provider incl. new format of tips section in "Add New Source"

* lower the amount of disk storage for each session to prevent issues while building cross platform (and disk overflow)

* imports according to goimport and code style

* make it possible to set custom urls to gitlab and github provider (only these could have a different host)

* split up oauth2 into multiple files

* small typo in comment

* fix indention

* fix indentation

* fix new line before external import

* fix layout of signin part

* update "broken" dependency

* Remove point column on ssh key setting page

* Remove un-used css

* Some cleaning

* Use octicon-key

* GPG commit validation

* Add translation

+ some little fix

* Move hash calc after retrieving of potential key + missing translation

* Add some little test

* Improve user openid list CSS and regenerate CSS

* Take navbar out of column
* Add styles to navbar
* Changed navbar classes
* Remove unneeded !important from index.css
* Remove unneeded !important from _explore.less

* Fix double borders on edit page (#1152)

* Add border modifications to less file

* initial stuff for oauth2 login, fails on:
* login button on the signIn page to start the OAuth2 flow and a callback for each provider
Only GitHub is implemented for now
* show login button only when the OAuth2 consumer is configured (and activated)
* create macaron group for oauth2 urls
* prevent net/http in modules (other then oauth2)
* use a new data sessions oauth2 folder for storing the oauth2 session data
* add missing 2FA when this is enabled on the user
* add password option for OAuth2 user , for use with git over http and login to the GUI
* add tip for registering a GitHub OAuth application
* at startup of Gitea register all configured providers and also on adding/deleting of new providers
* custom handling of errors in oauth2 request init + show better tip
* add ExternalLoginUser model and migration script to add it to database
* link a external account to an existing account (still need to handle wrong login and signup) and remove if user is removed
* remove the linked external account from the user his settings
* if user is unknown we allow him to register a new account or link it to some existing account
* sign up with button on signin page (als change OAuth2Provider structure so we can store basic stuff about providers)

* from gorilla/sessions docs:
"Important Note: If you aren't using gorilla/mux, you need to wrap your handlers with context.ClearHandler as or else you will leak memory!"
(we're using gorilla/sessions for storing oauth2 sessions)

* use updated goth lib that now supports getting the OAuth2 user if the AccessToken is still valid instead of re-authenticating (prevent flooding the OAuth2 provider)

Signed-off-by: Andrew Boyarshin <andrew.boyarshin@gmail.com>

* Markdown rendering overhaul

Cleaned up and squashed commits into single one.

Signed-off-by: Andrew Boyarshin <boyarshinand@gmail.com>

* Fix markdown API, add markdown module and API tests, improve code coverage

Signed-off-by: Andrew Boyarshin <boyarshinand@gmail.com>

* i18n button titles

* Improvements on notification page layout

* Notification count badge fixes

* Make table <tr> clickable

* Fix octicon aligment

* Fix use of AppSubUrl

* Use relative URLs

* Notifications - Mark as read/unread

* Feature of pinning a notification

* On view issue, do not mark as read a pinned notification

Notifications - Step 2

Signed-off-by: Manuel Kuhlmann <manuel@mkuhlmann.org>

Signed-off-by: Manuel Kuhlmann <manuel@mkuhlmann.org>