Added terminus font and urxvt documentation.

How to use terminus and urxvt and still get the powerline glyphs .
Make virtcol_current_gradient background color match line_current color

Fixes #449
Merge branch 'fix-449' into develop
Format in PowerlineLogger._log, not in pl.exception arguments
Merge branch 'no-exception-format' into develop
Merge pull request #365 from kierun/develop

Added terminus font and urxvt documentation.