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.
Use tuple in place of single-element list
Allow more then one -R be effective
Fix renderer_arg metavar
Add support for zsh local themes

Still missing: parser state

Ref #771
Make PS2 display something more meaningful: add continuation segment
Do not take number of subsegments into account, work without parser_state
Add tests for continuation segment
Make themes/shell/select.json look better
Also test zsh local themes
Add zpython support
Update zsh tests

Note: to make prompt fancy enough powerline-daemon should be used. Otherwise 
continuation prompt length is different from what was expected:

With daemon:

    user > env > path > if true ; then
                 then > fi

Without:

    user > env > path > if true ; then
    then > fi

Fixes #771 as I do not want to touch tcsh any longer
Also update solarized colorscheme
Remove failing test
Add powerline-lint support for new local themes