Some bug fixes.

Added a test for voting on arguments
Merge remote-tracking branch 'yaniv/master' into test_merge

Conflicts:
	src/issues/views.py
Fixed indentation issue after merge
Changed ranking properties of ProposalVoteArgument and added a united score property
Re-removed redundant templates and HTML content from ArgumentRankingVoteView responses.

Changed _do_vote behavior to match Yaniv's approach (reset is not a unique signal but a repeated voting)
replaced the up_down_vote view with ArgumentRankingVoteView
Added inteliJ files to gitignore
Merge remote-tracking branch 'yaniv/master' into test_merge

Conflicts:
	src/issues/views.py
Removed duplicate ProposalVoteArgumentVoteValue in models (merge artifact)
Added validation that the user voting on an argument has voted on the proposal the same as the argument's association.
Added interleaved for/against arguments property to Proposal