adjust fonts for Ubuntu

* removed otf fonts
* added version of Ubuntu Mono that's patched for Powerline glyphs
* changed default font
kludgy workaround for Powerline bug in GUI mode
disable the GUI menu
enable colorcolumn
make solarized vertsplit nicer in GUI
Update README, in case anyone else looks at this
make default GUI window narrower

While I often use VIM with vertical splits, I don't want a wide window to
be the default. Feels like it clutters up my desktop too much when I'm just
editing the odd file here and there.