Test syntax highlighting

Added a stylesheet and some CSS tweaks for syntax highlighting using {%
highlight fsharp %} etc.
Reduce tab size for formatting code
Reformat code using Jekyll/Pygments instead of Prettyprint
Reformatted another post to use Pygments formatting instead of Prettyprint
Reformatted another post to not use Prettyprint
More removal of prettyprint!
More syntax highlighting in posts, removing prettyprint
More code reformatting / removing prettyprint
More reformatting / removing prettyprint
Delete all the prettyprint code :)
Layout tweaks