* Santiation fix from Gogs

* Linting

* Fix build-errors

* still not working

* Fix all the things!

* gofmt

* Add code-injection checks

Also add unit tests

This PR fix the avatar bug described in #1114. This will fix random avatar is blank problem and potential delete avatars dir problem.

* bug fixed for org avatar caused by #1049

* use isfile only

* fix avatar enumable

* fix import style

* refactor for searching user

* fix like bug

* better format for builder cond

* 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)

* fix all the bugs in issues and pulls on dashboard

* small fix and refactor

* add method getRepoIDs for IssueList

This change corrects a few logging issues:

 * Standardized formatting errors with '%v'.
 * Standardized failure warning word usage.
 * Corrected an instance of using the standard log library when
   the gitea log library should be used instead.

- Add site-wide option DEFAULT_KEEP_EMAIL_PRIVATE.
- Add the new option to the install and admin/config pages.
- Add the new option to app.ini in the service section.
- Add the new option to the settings struct.
- Add English text strings to i18n.
- Add field KeepEmailPrivate to user struct.
- Add field KeepEmailPrivate to user form.
- Add option to UI.
- Add using noreply email address if user has "Keep Email Private".
An email address <LowerName>@<NO_REPLY_ADDRESS> is now used in commit
messages (and hopefully all other git log relevant places). The
change relies on the fact that git commands should use
user.NetGitSig().
- Add hiding of email address in UI, if user has set "Keep Email Private".
- Add condition to show email address only on explore/users and user
pages, if user has not set "Keep Email Private".
- Add noreply email in API if set "Keep Email Private".
- Add a new service setting NO_REPLY_ADDRESS. The value of this
setting is used as the domain part for the user's email address in
git log, iff he decides to keep his email address private.
If the user decides to keep his email address private and this
option is not set 'noreply.example.org' is used, which no MTA
should send email to.

Add NO_REPLY_ADDRESS to conf/app.ini.

* Check primary email address fields on CreateUser

As this check wasn't available, uid=1 (and possibly guests too, if registration is open) is able to register new users with existing email addresses. This leads to numerous 500 errors.

* Update user.go

* Lower the email first. Then check

* restrict creating organizations based on right on user

* revert bindata.go

* reverse vendor lib

* revert goimports change

* set AllowCreateOrganization default value to true

* revert locale

* added default value for AllowCreateOrganization

* fix typo in migration-comment

* fix comment

* add coments in migration

* Remove unused custom-alphabet feature of random string generator

Fix random string generator

Random string generator should return error if it fails to read random data via crypto/rand

* Fixes variable (un)initialization mixed assign
Update test GetRandomString

* golint fixed for modules/setting

* typo fixed and renamed UNIXSOCKET to UnixSocket

- Added public entries to reserved keywords list
- Rename variables
- Derped comment

From code.gitea.io/go-sdk/gitea
  To code.gitea.io/sdk/gitea

# Conflicts:
#	models/git_diff.go
#	models/issue.go
#	models/org.go
#	models/pull.go
#	models/repo.go