<bugfix>Message filter colors does not show in linux</bugfix>
<bugfix>Message filter colors does not show in linux</bugfix>

Adding a white background color fixed the problem
and makes the text visible with all themes

gui/debug.py:
- DebugView.__init__: added white background to filters
- DebugView.toggleType: changed "==" to "="

hjanime/VisTrails,minesense/VisTrails,minesense/VisTrails,Nikea/VisTrails,celiafish/VisTrails,celiafish/VisTrails,Nikea/VisTrails,celiafish/VisTrails,VisTrails/VisTrails,minesense/VisTrails,hjanime/VisTrails,hjanime/VisTrails,hjanime/VisTrails,VisTrails/VisTrails,minesense/VisTrails,minesense/VisTrails,hjanime/VisTrails,celiafish/VisTrails,VisTrails/VisTrails,VisTrails/VisTrails,Nikea/VisTrails,VisTrails/VisTrails,Nikea/VisTrails