Element positions should generally be set by stylesheets not hard-coded inline style attributes.
Made #note-file-list and breadcrumb styles simpler, more consistent.
Added Source Sans Pro font files, and adjusted fonts in stylesheets.

As I noted in comments at the top of `base.styl`, the TrueType Font
file was taken from the Google Fonts repository, and converted to other
font formats using the Font Squirrel web service. Using this method
will require settings bold and italic styles using the `font-family`
CSS property instead of `font-weight` and `font-style` properties.
Otherwise web browsers approximate their own version of bold and
italic, instead of using the actual bold and italic font faces.