doc parser should preseve tabs and whitespace in some blocks

[dante]

for example, you can use an examples: block in code comments for the parser to pick out. if you setup the the block to be indented, parser currently strips the whitespace from the start of the line, shifting all html-formatted content to the left. we should be able to setup formatted blocks in the comments.

[Neil Roberts]

Done using Markdown and the | character, as documented in style guide