Add sentry integration module

Module for enabling raven initializing to report to sentry.

Based on feedback from my presentation at odoo days 2014

Todo
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- [ ] Add git module version overwrite to raven
- [ ] Overwrite the except_orm message pop-up with something a little more friendly to the user
Is it necessary to try / except with that statement in __ openerp __ file ?

    'external_dependencies': {
    'python': ['raven', 'raven_sanitize_openerp', 'bzrlib'],
    },