Fixing issues of cache invalidation for multiple instances running in rhodecode.
- during server start always register all cache keys for all repositories
- Don't clear cache markers on start since multiple instances can clear each other out

Fixed status of changesets in preview windows
- show what status was pull-requests closed with
- added alternative logic for showing that status (disabled for now)

fixes #550 mercurial repositories comparision failed when origin repo had
additional not-common changesets + added regresion test for this

Remove null from revision column as for comments inside pull requests to work properly
new migration adds column for future simpler main page

Added huge diff protection for RSS/ATOM feeds.
It can really be a performance killer for huge diffs.

migrations: fix old hook values
- nicer notifications

More fixes to upgrade procedure,
- fix missing section on hook
- fixed missing inherit_default_permission column

Step6a for migrations from 1.3.6
to 1.4.0

new dulwich based implementation of added/modified/removed
functions for GIT changeset. Much faster some test up to 70% speed
improvements. Pure awesomeness !

re implemented affected_files function for git using dulwich
it speeds up things like 70%

added new suite of tests for VCS operations
- locking tests
- push pull tests
- added new ENV option to bypass re-creation of test enviroment

fixes issue #543, un-broken alternative gravatar option
- also now formatting is similar as other parts `{}`

changed the tests for search.
for >1 page we cannot guarantee the order, thus we cannot
check for particular revision.

sync alternative gravatar options to other .ini files
- changelog update

Implemented #532.
- now displaying username + full name for mapped users from RhodeCode

Implemented basic locking functionality.

- Reimplemented how githooks behave
- emaulate pre-receive hook
- install missing git hooks if they aren't already in repo

fixes issue #531, when extracting user email, we check it against the database,
and return user default email. Also if no email is present check the username
for matching targets.

added highlight lines field in ChangesetComments, will be used
later for attaching comments to blocks

fixed missing div on my_account + added nothing here yet when there are no
pull requests for user

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

Changed v.Set validation into our own that actually raises exceptions on missing values.
Added NotReviewedRevisions validator

fixes issue #524
- fixed search by filename
- added missing test for this search

Added optional flag to make_ui to not clean sqlalchemy Session.
Don't clear sqlalchemy session when using make_ui in admin repo form

use os.environ as a fallback for getting special info from hooks, this will allow
calling RhodeCode hooks from outside the system eg. via SSH
- also verify repo if it's a correct VCS throw 404 error otherwise