Hotfix 0.5.2

The pdf generation issues. The reverted commit was originally supposed to fix the issue in history pdf, where newline characters in full_note annotations would cause exceptions in footnote environment. Unfortunately, combined with invalid html markup it would cause other errors in the index pdf. 

The way to insert linebreaks in annotations is via the <p></p> tags, but since we can't rely on users to input valid html, I thought it is easier just to gsub the newline characters. 

Also added a formatting info tooltip, not quite github style I'm afraid but then we only support 3 tags.