Renames issue_from
Renames issue_to
Adds issue_relations migration
Adds license header
Adds changelog entry
Fixes factory
Renames issue_relations table to relations
Renames IssueRelation(Helper) source files
Renames IssueRelation constant to Relation
Adapts factories/fixtures
Adapts tests
Renames remaining occurences of issue_relation
Merge branch 'feature/rails3' into migration/issue_relations

Conflicts:
	app/models/project.rb
	app/models/relation.rb
	doc/CHANGELOG.md
Corrects translation
moves test to reflect moved test subject
removes remainins of issue from relation model
Merge branch 'feature/rails3' into migration/issue_relations
updates changelog
Merge branch 'feature/rails3' into migration/issue_relations

Conflicts:
	doc/CHANGELOG.md
Merge pull request #448 from opf/migration/issue_relations

[MIGRATION] Issue relations