* Sync interval specifed as duration string

* Changed mirror interval text

* make fmt

* Add MinInterval for mirror sync

* Use duration internally

* Changed min default to 10m

* make fmt

* Incorrect default

* Removed defaults in MustDuration()

* Add Mirror interval migration

* Default values corrected

* Use transaction during migration

* Change http 500 to page with error message

* Cleanup session.commit()

* Protected branches system

* Moved default branch to branches section (`:org/:reponame/settings/branches`).
* Initial support Protected Branch.
  - Admin does not restrict
  - Owner not to limit
  - To write permission restrictions

* reformat tmpl

* finished the UI and add/delete protected branch response

* remove unused comment

* indent all the template files and remove ru translations since we use crowdin

* fix the push bug

* Redirects for renamed repos

* Remove unused phrase from locales

* Add units concept for modulable functions of a repository

* remove unused comment codes & fix lints and tests

* remove unused comment codes

* use struct config instead of map

* fix lint

* rm wrong files

* fix tests

- Refactor code to use sync.UniqueQueue
- Closes #3509

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

Executed go fmt

getEngine() not handles DB parameters (#2972) (#2974)

Uses .AllCols() for Update in updateMirror()

Spanish traslation removed

Fixed a wrong way to ommit the --prune option in process.ExecDir() for MirrorUpdate function

Re: issues gogits/gogs#2863 and gogits/gogs#3231

As a result of modifications to the contents of the conf folder, `make bindata`
was run, causing an update to bindata.go.

Meta
-----
This commit will be rebased onto the 'develop' branch.

This commit improves templates readability, since all of them use consistent
indent with all template command blocks indented too.

1. Indents both HTML containers such as <div>, <p> and Go HTML template blocks
   such as {{if}} {{with}}

2. Cleans all trailing white-space

3. Adds trailing last line-break to each file

Merges repo/sidebar.tmpl with repo/header.tmpl and makes every repo page use
middleware.RepoRef() necessary to display information on this menu.

This is more inline with way GitHub looks like and feels much more natural and
in style with rest of the interface.

- update locales
- update README

The normal go get protocol is to show the go-import meta tag when ?go-get=1 is appended to the url. This commit implements that behaviour and cleans the go-get option from the repository settings page.