Enable OpenCommunity Backports and own repos.
Improvements and fixes to the hooks

* default version is now 7.0
* support OpenERP Community Backports
* fix stray character in stop hook
Work to modernize openerp-server
Add a simple test for now to check that deployment can work.
[ADD] Icon and other fixes from review
[mistotebe] This fixes the openerp-server charm. Also, it allows the user to set their own version in case they want to use OCB branches or custom code.