[FIX] website.snippet: display snippet editor button inline insead of 2 lines for the small boxes
[FIX] share: reduce risk of slowdowns during res.groups changes

Databases with thousands of users would experience
poor performance during any change to a group during
an update/install, caused by the prefetching of
all database users when the browse cache contains
most of the groups in the system.
Merge pull request #1338 from odoo-dev/8.0-fix-website-snippet-button-css-chm

[FIX] website.snippet: display snippet editor button inline insead of 2 lines for the small boxes
Merge remote-tracking branch 'upstream/8.0' into 8.0