Firefox pref access: qualifying global objects and adding exception logging.
Prompted by a user report (https://groups.google.com/forum/#!topic/markdown-here/ikXFqkP77Ws) of Firefox options access errors. Couldn't reproduce, so no idea if this fixes the problem.
Merge branch 'master' into development
Updated Highlight.js to version 7.4. This fixes issue #59.
Bumped version numbers. Prepping for release.
Merge pull request #142 from adam-p/development

v2.9.4 release