Extract NoticeObserver to Notice model

I think the Observer Pattern in Model is too ackward and need to be
avoid. This kind of stuff is delete on Rails 4 for example.
Rescue if there are failure in notification system

The rescue is catch and report on the errbit notification system

Fix #551
Delete useless get_script

The get_script can't works with asset_pipeline and it's already load

See #537
Stop using js on search pagination

The pagination don't work with the javascript request

See #528
Live action on data-action

The errbit.js add handler on data-action but this handler not works on
action change by Ajax. with a live, it's works now

Fix #526
add new feature merge [ci-skip]
add changelog about pr merged [ci-skip]
Update changelog with Fix bug

[ ci-skip ]
Add complete documentation about flowdock notification

See #511
Update index.md
Check backtrace on migration - issue #540
Merge pull request #541 from skorth/master

Fix issue #538
Add information about create indexes in README

When you deploy a Errbit instance, it's better to have index. A rake
rake do this job.

Update of README to add this information

Fix #522
Merge remote-tracking branch 'upstream/master'