All tags are put on a line by themselves to help with visual
diffing. Apparently this extra cosmetic whitespace causes problems inside p
tags for ppl who want to use `white-space: pre`. Not much hurt for visual
diffing in removing cosmetic whitespace for just p tags and can't think of
anything that would break because of this right now. So let's do it and wait
for things to break.
delimiters are not always 2 in length - $ being the exception. Also we have to
make sure to handle both $ and $$ delimiters.
Not proud of this solution but can't think of anything simpler right now - will
come back to this later hopefully.
