add related proposals API and merge with angular resources
Made Panu's $scope.relatedProposals model active
Merge branch 'proposal-sorting' into panus-proposal-sorting

Conflicts:
	app/assets/javascripts/angular/controllers/proposals_controller.coffee
	app/assets/javascripts/angular/services/api.coffee
	app/assets/templates/proposals/show.html.haml
	app/controllers/proposals_controller.rb
Manual Merge of spokenvote.coffee.erb
Manual Merge of Panu's Related Proposal Sorter
Fixed based on Pratik's suggested Route.rb change
Merge pull request #195 from kimardenmiller/panus-proposal-sorting

Panu's proposal sorting