Jbrowse JBrowse

Fixed jbrowse issue #176 (track label text sometimes disappearing after zoom in)
Chrome-specific bug was wrapping track-label-text to next line, which falls outside of track-label fixed height and therefore not seen. Adding "white-space: nowrap" to parent div (track-label) fixes.
See chromium bug report for more details on underlying issue: http://code.google.com/p/chromium/issues/detail?id=138918
https://github.com/GMOD/jbrowse/commit/7be108aa54273ee94405d73596c1...