Merge pull request #314 from mvexel/master

small improvements.
Merge pull request #315 from mvexel/master

adapting process.py to do post and put appropriately
Merge pull request #316 from mvexel/master

moving loader
adding bleach html sanitizer
adding html sanitizing
moving markdown parsing to client
Merge pull request #318 from mvexel/master

improvements to /api/challenges, and adding active to summary.
Merge branch 'master' of github.com:mvexel/maproulette
Merge remote-tracking branch 'upstream/master'