Filter discussion activity list for duplicates

Currently this just removes any duplicate discussion description edited
events from the view. Fixes #649
Merge branch 'master' of github.com:loomio/loomio into filter-discussion-activity-list
fixes specs
fix specs. TODO fix pending step on leave_group_steps
add logic for case when no one has voted. fixes #781
refactor discussion_css
Merge pull request #796 from loomio/refactor/discussion_css

Refactor/discussion css
Merge pull request #817 from loomio/bug/display_users_who_have_not_yet_decided

Add logic for case when no one has voted. fixes #781
fixes #823 makes discusssion disappear instantly
Merge pull request #826 from loomio/bug/discussions-show-up-after-delete

fixes #823 makes discusssion disappear instantly
Merge pull request #813 from loomio/filter-discussion-activity-list

Filter discussion activity list for duplicates
Merge branch 'master' of github.com:loomio/loomio into feature/public-groups-directory

* 'master' of github.com:loomio/loomio:
  fixes #823 makes discusssion disappear instantly
  refactor discussion_css
  add logic for case when no one has voted. fixes #781
  fix specs. TODO fix pending step on leave_group_steps
  fixes specs
  Filter discussion activity list for duplicates

Conflicts:
	db/schema.rb