Further fixes
Add/Remove hints now working properly. Hint feedback is working.
Merge branch 'master' of https://github.com/yoavfreund/Webwork_AdaptiveHints into junk
Merge branch 'junk' of https://github.com/yoavfreund/Webwork_AdaptiveHints into junk
Delete HintAnswer rest api call and hint attempts database table.  Other small fixes