Imported some of the GPLv3'd changes from RhodeCode v2.2.5.

This imports changes between changesets 21af6c4eab3d and 6177597791c2 in
RhodeCode's original repository, including only changes to Python files and HTML.

RhodeCode clearly licensed its changes to these files under GPLv3
in their /LICENSE file, which states the following:
The Python code and integrated HTML are licensed under the GPLv3 license.

(See:
https://code.rhodecode.com/rhodecode/files/v2.2.5/LICENSE
or
http://web.archive.org/web/20140512193334/https://code.rhodecode.com/rhodecode/files/f3b123159901f15426d18e3dc395e8369f70ebe0/LICENSE
for an online copy of that LICENSE file)

Conservancy reviewed these changes and confirmed that they can be licensed as
a whole to the Kallithea project under GPLv3-only.

While some of the contents committed herein are clearly licensed
GPLv3-or-later, on the whole we must assume the are GPLv3-only, since the
statement above from RhodeCode indicates that they intend GPLv3-only as their
license, per GPLv3§14 and other relevant sections of GPLv3.

Enabled compare engine for tags
Implemented compare engine for git repositories

Added h.tooltip to all places that tooltip_title is used.
- improved escaping of < and > inside tooltips

Implements #304
hashes in relevant places are displayed using monospaced font.

implemented #44 - branch filtering in changelog, aka branch browser
- changed GUI on tags/branches to not use images.

reimplemented tooltip, refactored tooltip_title into title for proper html,
and changed display strategy to right to temporary fix display problem with large tooltips

Fixes for raw_id, needed for git
Renamed hg controller to home
css html changes