* Force-push to base repo's ref/pull/#/head

Fixes force-pushing to pull request branches, otherwise failing with:

[...gitea/models/pull.go:1022 AddTestPullRequestTask()] [E] PushToBaseRepo: Push: exit status 1 - To /path/to/gitea-repositories/org/repo.git
 ! [rejected]        issue-fix -> refs/pull/20/head (non-fast-forward)

* format

* Change how merged PR commits and diff are made

* Update code.gitea.io/git dependency

* Fix typo

* Remove unneeded local variable

* Remove hardcoded paths to fix randomly failing tests

* Use correct function for merge path

* 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

* refactor struct's time to remove unnecessary memory usage

* use AsTimePtr simple code

* fix tests

* fix time compare

* fix template on gpg

* use AddDuration instead of Add

* Fix: table `pull_request` won't be updated correctly

* Update also status column when manually merged

* use AfterLoad instead of AfterSet on Structs

* fix the comments on AfterLoad

* fix the comments on action AfterLoad

* reduce usage of allcols on update

* fix bug and tests

* Improve issue indexer

* Fix new issue sqlite bug

* Different test indexer paths for each db

* Add integration indexer paths to make clean

* Update code.gitea.io/git

* Update function calls

* govendor fetch

* Fix activity feed

Preserve actions after user/repo name change

* Add missing comment

* Fix migration, and remove fields completely

* Tests

when merge pull request

* Move new fields to object creation (use reference)
 * Vendor: Update SDK

* Add length check for the return string

* Differentiate error paths and logging messages

* Rectify error message

When an open pull request got manually merged mark the pull request as
merged

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.

* Allow custom public files

* Gofmt code, lots of places not related to this pr

* Add a process.Manager singleton with process.GetManager()

* Use process.GetManager everywhere

* Fix godoc comments for process module

* Increment process counter id after locking the mutex

Unit tests for models/pull.go

* Speed up conflict checking in pull request creation

In order to check conflicts of a PR, we set up a working tree by
cloning the base branch, which is quite time-consuming when the repository is huge.
Instead, this PR uses `git read-tree` and `git apply --check --cached` to check conflicts.

For #258

* Use $GIT_INDEX_FILE instead of --index-output to avoid lockfile problem

The lockfile gets renamed to the final destination after the operation
finishes. But it must be located in the same filesystem, which prevents
us from using /tmp.

* Temporary file names should not prefixed with '-'

Delete old temp local copy before we create a new temp local copy

Also move duplicated code into repo.APIFormat(..)

* Fix #344 (regression in PR-API #248)

Suppress the error when we're removing a file that may not exist

* golint fixed for modules/setting

* typo fixed and renamed UNIXSOCKET to UnixSocket

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