Add sentry integration module

Module for enabling raven initializing to report to sentry.

Based on feedback from my presentation at odoo days 2014

Related project: https://github.com/gisce/openerp-sentry

~~Todo~~
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- [x] Add git module version overwrite to raven
- [x] Overwrite the except_orm message pop-up with something a little more friendly to the user **(Help wanted)**
- [ ] Enable tests with sentry server in travis
Hi

Please removed "bzrlib" and "git" dependancies on __openerp__.py, because i only use git, and convert bzr repo with fast-export and fast-import, and i cannot install this module. The protection on the odoo_sentry_client.py file is adequacy to check if bzrlib and git is installed

Regards,