tweet buttons get correct total score for randomize
use floats for checking metadata feedback
Merge branch 'master' of https://github.com/Stanford-Online/class2go into jbau-random-psets
display correct total for edit mode randomized pset
slightly more efficient and cleaner __unicode__
Merge pull request #2396 from Stanford-Online/jbau-random-psets

Fixes to handle exam total score for randomized problems