Reverted commit 57a1212105 that introduced an unnecessary
call to has_group, as it could be done un share_wizard.py once for the session.
Removed the group_share_user, not necessary anymore.
New features: can share to groups if user has "Share / User (Extended)"
group. Warning message if user does not have email and cannot share by
email. Names of sharing groups are now hidden in ORM access denied messages.
Better error reporting.
UI: more user-friendly labels, titles. More visibible button in web client.
Bugfixes: better handling of sharing objects with _inherits, can combine
ir.rules if already exist for same (object,group). Button is now hidden
in web client if user is not in "Share/User" group.
bzr revid: odo@openerp.com-20110408133608-vmdrzfeo0dz28wer
Bhavik Bagdiya