Put Canvases to the right of the code but at the top of the page.

Hovering switches the canvases to their original size.
Convert() now takes a bitmask: kInterpretedOutput interprets the file, kCompiledOutput uses ACLiC and if combined with kForceOutput existing PNGs are ignored.
Convert() now has a new parameter (context) which is written verbatim to the output file; useful e.g. for context links (up, next,...)


git-svn-id: http://root.cern.ch/svn/root/trunk@26734 27541ba8-7e3a-0410-8455-c3a389f83636