CP-6093: Filter by Location ToolStripDropDownButton: only add ShowAll item if there
are actually items to show. Button enablement on Events page.

Signed-off-by: Konstantina Chremmou <konstantina.chremmou@citrix.com>
CP-6093: Custom drawing for the main window navigation buttons.

Signed-off-by: Konstantina Chremmou <konstantina.chremmou@citrix.com>
Merge branch 'master' of git://hg.uk.xensource.com/carbon/trunk/xenadmin