More HTML::Pipeline filters

The big part of this MR is a feature that is intended to test the entire Markdown-parsing process from beginning to end. See `spec/support/markdown_feature.rb` and `spec/features/markdown_spec.rb`.

One big thing this MR fixes is not being able to type a `<` or `>` anywhere. It now gets properly escaped.

This MR also adds three more custom HTML::Pipeline filters:

### AutolinkFilter

Similar to the built-in Autolink filter in that it still uses Rinku for standard http and ftp links, but then does some further processing to allow auto-linking of any URI scheme. See internal issue https://dev.gitlab.org/gitlab/gitlabhq/issues/2239

### SanitizationFilter

Created a simple custom SanitizationFilter that sub-classes the default one and adds our custom whitelisting.

### TableOfContentsFilter

Adds the anchor links to each header. This removes some processing from our Redcarpet renderer.

Closes #800, #1015, #1528, #1549

Closes GitHub [8535](https://github.com/gitlabhq/gitlabhq/issues/8535)

See merge request !584

Add link to services api doc.

Just a one-line change to link in the services api doc.

I'm curious though. Only gitlab-ci and hipchat are supported.  Would you accept a pull request for the other services? Actually I [submitted](http://feedback.gitlab.com/forums/176466-general/suggestions/7667256-add-api-calls-for-all-services-in-a-project) that last question to the feedback tool.

See merge request !544

While `escape_once` will create this HTML entity, Nokogiri always
translates it back before it gets to IssueReferenceFilter, so there
should be no danger of erroneous issue links.

This just extends the HTML::Pipeline::SanitizationFilter with our custom
whitelist.

Removes header and table of contents processing from Redcarpet renderer.

Update upgrader doc to point to 7.10.1.

See merge request !594

Fix DB error when trying to tag a repository

Steps to reproduce: Go to a project settings, add tags, click on save changes

Observed behavior: Error 500

```
    PG::Error: ERROR:  column "taggings_count" does not exist
        LINE 1: UPDATE "tags" SET "taggings_count" = COALESCE("taggings_coun...
```

Ran `rake acts_as_taggable_on_engine:install:migrations`, removed the first
migration that created the `tags` and `taggings` table, and added the rest.

* Closes #1512
* Closes #1550
* Closes https://github.com/gitlabhq/gitlabhq/issues/6867
* Closes https://github.com/gitlabhq/gitlabhq/issues/9194

See merge request !577

Show incompatible projects in Google Code import status

Using Google Code import with a JSON file that contained only one Subversion project led to confusion
over whether the system was working. Display the list of valid projects if there are any, and show a list of incompatible projects. Provide tips on how to retain issue data after conversion.

Closes #1531

## Screenshots

Before:

![Screen_Shot_2015-04-29_at_12.46.41_AM](https://gitlab.com/stanhu/gitlab-ce/uploads/16ea5a99cbace48cd2f2c238b5f73f4e/Screen_Shot_2015-04-29_at_12.46.41_AM.png)

After with no projects available (notice the button is hidden):

![Screen_Shot_2015-04-30_at_1.34.38_AM](https://gitlab.com/gitlab-org/gitlab-ce/uploads/43c612cdcbab181713e5764e2f38a04e/Screen_Shot_2015-04-30_at_1.34.38_AM.png)

After with 1 valid and 1 incompatible project:

![Screen_Shot_2015-04-30_at_1.37.26_AM](https://gitlab.com/gitlab-org/gitlab-ce/uploads/b5bcbd304206a996932e5208ef54a071/Screen_Shot_2015-04-30_at_1.37.26_AM.png)

See merge request !586

Fix "Revspec not found" errors when viewing diffs in a forked project with submodules

## What does this MR do?

This MR fixes an error that occurs when viewing diffs in a forked project with submodules.

### Are there points in the code the reviewer needs to double check?

Testing this code was tricky. The only way this problem shows up is if the origin project does NOT have the submodule update commit. The introduction of gitlab-test-fork serves that purpose: it contains a submodule update not present in gitlab-test.

### Why was this MR needed?

A user would receive a 500 error when trying to view a merge request with a submodule update. #1413 has details on how to reproduce this issue.

### What are the relevant issue numbers / [Feature requests](http://feedback.gitlab.com/)?

#1413

See merge request !512

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Conflicts:
	app/views/layouts/_head_panel.html.haml

Merge branch 'container-class-reloaded' of https://github.com/Soullivaneuh/gitlabhq into Soullivaneuh-container-class-reloaded

Don't allow a merge request to be merged when its title starts with "WIP".

Addresses private issue https://dev.gitlab.org/gitlab/gitlabhq/issues/2078

![Screen_Shot_2015-04-30_at_15.47.03](https://gitlab.com/gitlab-org/gitlab-ce/uploads/9035743e6f482a9c31cf86d84388074c/Screen_Shot_2015-04-30_at_15.47.03.png)

See merge request !590

Update 7.9-to-7.10.md

Importing a JSON file with only one Subversion project lead to confusion
over whether the system was working. Provide status why these projects
could not be imported directly.

Closes #1531

Improvements to search layout

Improve search layout to match new UI style and make it more mobile-firendly

See merge request !585

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>