Closes #3182

* Fix #3321: commit tag shortener

* Check short commit

* remove debug

* Edit unit tests

* Show 10-char short SHA

* Implement wiki mirroring, add Update mirrors operation to admin dashboard

* bindata.go update after merge

* Implement checking Git repo endpoint existence, support for BB included

* Remove admin dashboard operation
Fix bindata.go

* Apply gofmt to repo model file

* Try to remove bindata from PR

* Revert accepted wiki names change in favor of better system

* Remove unused imports

* add mirror::GLOBAL_INTERVAL on app.ini

* rename key to DEFAULT_INTERVAL

* add key on default app.ini + move code

* Add support for federated avatars

Fixes #3105

Removes avatar fetching duplication code
Adds an "Enable Federated Avatar" checkbox in user settings
(defaults to unchecked)

Moves avatar settings all in the same form, making
local and remote avatars mutually exclusive

Renames UploadAvatarForm to AvatarForm
as it's not anymore only for uploading

* Run gofmt on all modified files

* Move Avatar form in its own page

* Add go-libravatar dependency to vendor/ dir

Hopefully helps with accepting the contribution.
See also #3214

* Revert "Add go-libravatar dependency to vendor/ dir"

This reverts commit a8cb93ae64.

* Make federated avatar setting a global configuration

Removes the per-user setting

* Move avatar handling back to base tool, disable federated avatar in offline mode

* Format, handle error

* Properly set fallback host

* Use unsupported github.com mirror for importing go-libravatar

* Remove comment showing life exists outside of github.com

... pity, but contribution would not be accepted otherwise

* Use Combo for Get and Post methods over /avatar

* FEDERATED_AVATAR -> ENABLE_FEDERATED_AVATAR

* Fix persistance of federated avatar lookup checkbox at install time

* Federated Avatars -> Enable Federated Avatars

* Use len(string) == 0 instead of string == ""

* Move import line where it belong

See
https://github.com/Unknwon/go-code-convention/blob/master/en-US/import_packages.md

Pity the import url is still the unofficial one, but oh well...

* Save a line (and waste much more expensive time)

* Remove redundant parens

* Remove an empty line

* Remove empty lines

* Reorder lines to make diff smaller

* Remove another newline

Unknwon review got me start a fight against newlines

* Move DISABLE_GRAVATAR and ENABLE_FEDERATED_AVATAR after OFFLINE_MODE

On re-reading the diff I figured what Unknwon meant here:
https://github.com/gogits/gogs/pull/3320/files#r73741106

* Remove newlines that weren't there before my intervention

- Try to reduce memory allocations
- Add possibility to disable diff highlight (can improve performance for large diffs)
- Tweaking with cost for prettier (cleaner) diffs
- Do not calculate diff when the number of removed lines in a block is not equal to the number of added lines (this usually resulted in ugly diffs)

Enable/disable input based on user chosen options for wiki and issue tracker.

Sets all avatars to use PNG image format.
Keeps avatars consistent at 290x290px resolution.

Signed-off-by: Dennis Chen <barracks510@gmail.com>

RepoLink -> Link, RepoRelLink -> RelLink, FullRepoLink -> FullLink

* Add MaxDisplayFileSize setting

* Don't show files that are too large

* Localized FileTooLarge

* Change IsFileTooBig => IsFileTooLarge