We've fixed some leaks in peg-markdown and added a few functions for
use in libraries. It's still not suitable for use in long-running
processes but RSS growth per-parse has decreased by about 10x.
Also, note that the peg-markdown submodule has been changed to point
to git://github.com/rtomayko/peg-markdown.git -- you may need to
remove the submodule config entry from your .git/config file and run
the submodule:init rake task.