Merge pull request #236 from egor83/master

Setting app version back to master.
Merge pull request #238 from egor83/master

Removing last references to votes
front end changes to handle None from the datastore
Merge pull request #239 from anubhavsinha/#233_fron_end_changes

front end changes to handle None from the datastore
Fixing exception when viewing challenge page

while not logged in (fixes #171).