Remove the icons that are not mirrored to regular locations. And moved the icons that need mirroring to mirrored locations. Replaced "octicon-chevron-right" with new set of mirrored icons from fontello

Based on issue #688 advice, used webfont-dl to download roboto font and
modified base stylesheet to reference roboto locally instead of
referencing Google hosted version.

Used webfont-dl with url
http://fonts.googleapis.com/css?family=Roboto:300,400,500,600,700&subset=latin,cyrillic-ext,greek-ext,greek,vietnamese,latin-ext,cyrillic
to download Roboto font to local directory.  Url originally declared in
base.less.

The url requestd 300,400,500,600, and 700, but it looks like only
300,400,500, and 700 are supported.