Fix ok-icon in membership widget

Fix ok-icon doesn't show in assign list
Use icon-font not bitmap-icon
Tweak CSS

Change-Id: I256a7dbb36da1da75a63a72a5bc7562d5777a2c5
Closes-Bug: 1354510
Updated the documentation of the OPENSTACK_NEUTRON_NETWORK settings.

Change-Id: I5f39629fade22999f991500e68cd84edad0014bb
Merge "Fix ok-icon in membership widget"
Merge "Updated the documentation of the OPENSTACK_NEUTRON_NETWORK settings."