Multiple links on the same line are currently not recognized correctly.

This changes the regex to look for a hash from 7 to 40 characters,
to match the use of abbreviated hash lookups in both git and github.
The restriction of not being a pure number is also removed because
1234567 is now considered a valid abbreviated hash, as is deadbeef.

A note has been added to the top of the code to state that the
literal regex match is fine, but no extra validation is currently
performed so some false positives are expected.

A future change could ensure that the hash exists in the repository
before rendering it as a link, although this might incur a slight
performance penalty.

Reverts part of commit 4a46613 and fixes #2053.

* Fix commit sha1 URL rendering in markdown

* Add unit test for commit sha1 markdown rendering when sha1 has space before it

* Change to better variable name

* Santiation fix from Gogs

* Linting

* Fix build-errors

* still not working

* Fix all the things!

* gofmt

* Add code-injection checks

Amended with string to bool change in API SDK.

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>

* Improve issue references in markdown. (#3436)

* Fix build

* Fix lint

* Fix comment typo

* golint fixed for modules/setting

* typo fixed and renamed UNIXSOCKET to UnixSocket

- Update import paths from github.com/go-gitea to code.gitea.io
- Fix import path for travis

See https://docs.travis-ci.com/user/languages/go#Go-Import-Path

* Fix mention in comments like (@dblk)

* Better fix to avoid making link for "Hello@DblK"

- Detect non-exist commit and return 404 not 500

commit 0afcb843d7
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Sun Jul 31 17:13:29 2016 -0600

    Removed Upload stats as the upload table is just a temporary table

commit 7ecd73ff55
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Sun Jul 31 08:42:41 2016 -0600

    Fix for CodeMirror mode

commit c29b9ab531
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Sun Jul 31 08:03:33 2016 -0600

    Made tabbing in editor use spaces

commit 23af384c53
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Sun Jul 31 07:56:46 2016 -0600

    Fix for data-url

commit cfb8a97591
Merge: 7fc8a89 991ce42
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Sun Jul 31 07:42:53 2016 -0600

    Merge remote-tracking branch 'gogits/develop' into feature-create-and-edit-repo-file

    Conflicts:
    	modules/bindata/bindata.go
    	public/js/gogs.js

commit 7fc8a89cb495478225b02d613e647f99a1489634
Merge: fd3d86c c03d040
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Sun Jul 31 07:40:00 2016 -0600

    Merge branch 'feature-create-and-edit-repo-file' of github.com:richmahn/gogs into feature-create-and-edit-repo-file

commit fd3d86ca6bbc02cfda566a504ffd6b03db4f75ef
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Sun Jul 31 07:39:44 2016 -0600

    Code cleanup

commit c03d0401c1049eeeccc32ab1f9c3303c130be5ee
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Fri Jul 29 15:38:23 2016 -0600

    Code cleanup

commit 98e1206ccf9f9a4503c020e3a7830cf9f861dfae
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Thu Jul 28 18:36:01 2016 -0600

    Code cleanup and fixes

commit c2895dc742f25f8412879c9fa15e18f27f42f194
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Thu Jul 28 18:24:04 2016 -0600

    Fixes per Unknwon's requests

commit 6aa7e46b21ad4c96e562daa2eac26a8fb408f8ef
Merge: 889e9fa ad7ea88
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Thu Jul 28 17:13:43 2016 -0600

    Merge remote-tracking branch 'gogits/develop' into feature-create-and-edit-repo-file

    Conflicts:
    	modules/bindata/bindata.go
    	modules/setting/setting.go

commit 889e9faf1bd8559a4979c8f46005d488c1a234d4
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Fri Jul 22 14:09:18 2016 -0600

    Fix in gogs.js

commit 47603edf223f147b114be65f3bd27bc1e88827a5
Merge: bb57912 cf85e9e
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Fri Jul 22 14:07:36 2016 -0600

    Merge remote-tracking branch 'gogits/develop' into feature-create-and-edit-repo-file

    Conflicts:
    	modules/bindata/bindata.go
    	public/js/gogs.js

commit bb5791255867a71c11a77b639db050ad09c597a4
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Fri Jul 22 14:02:18 2016 -0600

    Update for using CodeMirror mode addon

commit d10d128c51039be19e2af9c66c63db66a9f2ec6d
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Tue Jul 19 16:12:57 2016 -0600

    Update for Edit

commit 34a34982025144e3225e389f7849eb6273c1d576
Merge: fa1b752 1c7dcdd
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Tue Jul 19 11:52:02 2016 -0600

    Merge remote-tracking branch 'gogits/develop' into feature-create-and-edit-repo-file

    Conflicts:
    	modules/bindata/bindata.go

commit fa1b752be29cd455c5184ddac2ffe80b3489763e
Author: Richard Mahn <richard_mahn@wycliffeassociates.org>
Date:   Fri Jul 15 18:35:42 2016 -0600

    Feature for editing, creating, uploading and deleting files

* Fix #3321: commit tag shortener

* Check short commit

* remove debug

* Edit unit tests

* Show 10-char short SHA

Replace spaces with "%20" in "urlPrefix", before markdon processing.
The spaces were causing blackfriday (markdown processor) to behave
strange. This fixes #2545.