Fix hub filter in proposals list
Merge pull request #180 from tispratik/may3_fix_filters

Issues

  - The main index page should show "trees", not every proposal as it does now.  Seems that might be the missing ".roots" part

  - proposals?filter=active should sort by votes_in_tree, which it appears to no longer do.

  - Searching a Group, then selecting My Votes "forgets" the Group. It should remember.

  - "My Votes" now ignores the hub ... e.g.  (proposals?filter=my_votes&hub=8) just gives me all my votes for all hubs.

Merging with the assumption we'll fix these items this evening.

Thank you, Pratak! :baby_chick: