css: linear-gradient do not have 'top' but 'to bottom'

- according to https://developer.mozilla.org/en-US/docs/CSS/linear-gradient

css: opacity is a float and cannot be px

Undoing parts of 20940ddb5f4d.

css: drop -moz-border-radius and -moz-box-shadow

Firefox 4.0 added support for border-radius and box-shadow. Firefox 13.0 and
later emits errors for -moz-border-radius. There is thus no reasons to keep the
old styles.

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

in case we turn on celery, and connection fails, set the global flag CELERY_ON to false, helps with odd
problems during this state

added same switch to logic for tags and bookmarks containing /.
added "at" GET params to visualize switching for revisions with /

switch to branch: handle slashes in branch names

In git, having slashes in branch names are not uncommon.

We cannot use a branch name with slashes in the url, so in that case, we
use the changeset id instead like we already do for tags and bookmarks.

Fixes #654

Update changeset cache should use non-cache version of repo if given attribute is empty, it's easier to controll how changesets are udpated
The quick update logic in base controller get's cached version and updates, while any other call will use non-cached version

iterate over repos groups for bool() calls to actually work on it.
fixes some issues with correctly displaying if there are no groups you have permission to.

further cleanup of UsersGroup

Renaming some names ... but trying not to change API or database scheme.

changelog: don't select all checkboxes in the middle

The changesets in the log might not be linearly connected and intermediate
changesets might not be a part of the operation the range is used for.

Some way of highlighting the two selected changesets and some radio button
functionality would however be nice.

"Users groups" is grammatically incorrect English - rename to "user groups"

- and same story with "repositories groups"

This will only change the user facing texts. Names of files, modules, functions
and variables should be changed too.

moved out password reset tasks from celery, it doesn't make any sense to keep them there, additionally they are broken
in when executing _(), and url() calls. This fixes issue #572

--version command should be safe, and bare no modifications
- improved subprocess calls error detection
- fixed I/O read on closed file errors

implemented #689 Deleting Repositories with Forks Should Be Easier
- optionally detach or delete forks associated to repo

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

revision extraction function shouldn't be so eager, just extract commits that are
surrounded with spaces, or they are at beginning of the whole string
- wrote tests for that
- used parametrized for other tests

cleanup would recurse into every leaf and could thus not be used on lots of
large repositories.

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

move permission check of write access to repo groups inside a form.
- it's runned via create/edit/fork forms
- in case we have disabled repo creation, it will check root location write access for people that are not super admins, or have explicity create repo permission
- in case there's a group value passed to form, it checks just admin or write access

fixes #762, LDAP and container created users are now activated based on
the registration settings in permissions

make the htsts headers optional and stored in .ini file.
also don't use it with DEBUG

fixes issue #756 cleanup repos didn't properly compose paths of repos to be cleaned up.
- it just worked on repos on root filesystem

git hook handler shouldn't ever use cache instances
- moved cache invalidation into finally block so we invalidate at latest possible stage
- added scm_instance_no_cache property to get non cached scm instances always

reposcann should skip directories with starting with '.'
some code cleanup, moved all skipping to get_repos function

fixes for issue #731, update-repoinfo sometimes failed to update data when changesets
were initial commits

improved extraction of user from changeset when sending notification.
Fallback to repo owner if we cannot get the user