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.

templates: enforce more consistency by being less flexible in templates

All pages must define page_nav.

context_bar may only be used on relevant repository pages, and the 'current'
parameter is mandatory.

pullrequests: fix non-js defaults for repo owner

Owner of default_other_repo was never sent to the the template ... and the
template would fail if it had been sent. Instead we set default_other_repo_info
to the other_repos_info struct and use that to find the owner.

pullrequest: just replace children of other_ref when other_repo changes

We were inserting a full select statement as innerHTML of a select and would
thus get nested select statements. IE did not render that correctly ... and
other browsers did strange things.

Instead we now create a in memory DOM object and move the optgroups. After
appending children to the selector we have to set selectedIndex on all
browsers.

compare/pullrequest: introduce merge parameter

This is more correct and flexible than the old way of looking on same/different
repo.

notifications changes
- closing pull requests will give notification about it
- more detailed notifications about commenting on changesets and pull requests

review members are dynamically changed based on selected other_repo owner
- implemented pyroutes for smarter JS url handling
- fixed some old style global var routing

fixed pull-requests with cherry picking changesets
- fixed tests for them

pull request: update changeset list automatically - remove refresh icon

With most of the UI giving immediate response it was confusing that we had to
press 'refresh' manually'. The icon could also be misunderstood as a 'swap'
symbol or as reload/reset.

compare: swap org and other when they refer to different repos, ie are pull request style

Pull requests will have a different from/to description - but in a consistent
and slightly better way that can be improved later.

A pull request diff is empathic: "How will this look for the peer I'm proposing to" style.

compare: rename optional compare_url parameter repo to other_repo

At the same time it is placed before other_ref_type and other_ref. Just to keep
a logical flow and (a new) consistency that will help the next refactoring.

compare and diff: remove unused "bundle" functionality

The 'bundle' parameter was never set, incoming_changesets was thus always
False, remote_compare was thus always False, and InMemoryBundleRepo and
bundlerepo was neverused.

Basic implementation of cherry picking changesets
for pull request, ref #575

#590 Add GET flag that controls the way the diff are generated, for pull requests we want to use non-bundle based diffs,
That are far better for doing code reviews. The /compare url still uses bundle compare for full comparision including the incoming changesets.
- Fixed tests

swap the select values with revisions dynamically when switching the repos on pull request view
- fix the partial ajax request that should never do redirect

Load generated revs while switching to other sources of pull-requests.
Issue before was that extra tags or bookmarks weren't present in the dropdown

added option to remove members added using autocomplete widget from pull
request

Added autocomplete widget for pull request reviewers, in exchange of 90s style
multi select widget

Added dynamic data loading for other repo we open pull request against
- fixed notification emails, now with link to comment or status change in given pull request

Added basic models for saving open pull requests
- added pull-request models
- added pull-requests notifications into inbox