* Markdown: enable some more extensions

Improve Markdown-rendering by enabling some extensions:

- enable definitions lists
- enable footnotes
- enable header-ids and automatically generate header-ids (for linking to README-sections or creating table-of-contents for larger READMEs)

* Markdown: update and exted tests

Update and add tests for additionally enabled Markdown-extensions.

redirect_to holds a value that we want to redirect back to after login.
This value can be a path with intentonally escaped values and we
should not unescape it.

Fixes #4475

Resolve #6004

Include the current CustomPath location in the admin section and also
display GITEA_WORK_DIR and/or GITEA_CUSTOM env var if they are set.

Right now there is no easy way to see this information, and if you try
and help most users they won't be able to tell you anything about these
values -- just that their custom template isn't working, files aren't in
the right place, etc... Now you can see all paths and if they were set
by ENV or not.

Partially implement #770.
Add "Default Webhooks" page in site admin UI.
Persist to the existing webhooks table, but store with RepoID=0 and OrgID=0.
Upon repo creation, copy the set of default webhooks into the new repo.

Fix #1173

Fix #4339

Fixes #6265

* Use PathUnescape instead of QueryUnescape when working with branch names

Currently branch names with a '+' fail in certain situations because
QueryUnescape replaces the + character with a blank space.

Using PathUnescape should be better since it is defined as:

// PathUnescape is identical to QueryUnescape except that it does not
// unescape '+' to ' ' (space).

Fixes #6333

* Change error to match new function name

* Add new util function PathEscapeSegments

This function simply runs PathEscape on each segment of a path without
touching the forward slash itself. We want to use this instead of
PathEscape/QueryEscape in most cases because a forward slash is a valid name for a
branch etc... and we don't want that escaped in a URL.

Putting this in new file url.go and also moving a couple similar
functions into that file as well.

* Use EscapePathSegments where appropriate

Replace various uses of EscapePath/EscapeQuery with new
EscapePathSegments. Also remove uncessary uses of various
escape/unescape functions when the text had already been escaped or was
not escaped.

* Reformat comment to make drone build happy

* Remove no longer used url library

* Requested code changes

* Add lang specific font stacks

* Force font changes

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Fix icons

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Fix octicons and icons

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Just override the semantic ui fonts only

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Missed the headers... override them too

* Missed some more semantic ui stuff

* Fix PT Sans

Signed-off-by: Andrew Thornton <art27@cantab.net>

* More changes

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Squashed commit of the following:

commit 7d1679e907
Author: Mike L <cl.jeremy@qq.com>
Date:   Wed Mar 13 13:53:49 2019 +0100

    Remove missed YaHei leftover from _home.less

commit 0079121ea9
Author: Mike L <cl.jeremy@qq.com>
Date:   Wed Mar 13 12:03:54 2019 +0100

    Fix overdone fixes (inherit, :lang)

commit 62c9199159
Author: Mike L <cl.jeremy@qq.com>
Date:   Wed Mar 13 02:29:10 2019 +0100

    Fix elements w/ explicit lang (language chooser)

commit b3117587aa
Author: Mike L <cl.jeremy@qq.com>
Date:   Tue Mar 12 20:17:26 2019 +0100

    Fix textarea also (to match body)

commit 81cedf2c30
Author: Mike L <cl.jeremy@qq.com>
Date:   Tue Mar 12 19:41:39 2019 +0100

    Revert css temporarily to fix conflict

commit 80ff82797f
Author: Mike L <cl.jeremy@qq.com>
Date:   Tue Mar 12 19:15:30 2019 +0100

    Tweak CJK, fix Yu Gothic, more monospace inherits

commit 581dceb9a8
Author: Mike L <cl.jeremy@qq.com>
Date:   Mon Mar 11 13:09:26 2019 +0100

    Add Lato for latin extd. & cyrillic, improve CJK

* update stylesheet

* add scripts/test-local.sh and fix CONTRIBUTING.md

- fixes #6243
- partial fix for #6269

Signed-off-by: Steve Traugott <stevegt@t7a.org>

* remove reference to possible automated drone run

* remove bash version of drone-cli test script

* fix issue number links in testing instructions

* remove scripts/test-local.sh

Elaborate more on the code search storage space requirement

* split setting.go to multiple files

* fix lint

* Fix ParsePatch to work properly with quoted diff --git string

Currently ParsePatch fails when a diff contains a quoted diff line like:

diff --git "a/file" "b/file"

This patch makes it properly parse the line when that happens.

Fixes #6309

* Add test for regular case while here

* Simplify string modification

* Use url.PathEscape to escape the branchname

* GetRepositoryByOwnerAndName should also have url.PathEscape as the owner and reponame are provided by the client

Add  Gitea Extension for Visual Studio

* update git vendor to fix wrong release commit id and add migrations

* fix count

* fix migration release

* fix tests

* Add support for client basic auth for exchanging access tokens

* Improve error messages

* Fix tests