resolves #538 add pygments as source highlighter option

- also fix bug in CodeRay stylesheet
resolves #546 fix greedy comment blocks and paragraphs
Merge pull request #547 from mojavelinux/fix-greedy-comments

resolves #546 fix greedy comment blocks and paragraphs
Merge pull request #545 from mojavelinux/pygments-highlighter

resolves #538 add pygments as source highlighter option