always render the table, even if it's empty. this allows jquery to have an anchor to put content in. also explicitly add the <tbody> tag since the corresponding jquery code uses that one. this worked before because (at least) chrome adds implicit <tbody> tags if missing and the table isn't empty. fixes #384.
cucumber scenario for adding issue relations through ajax
some code improvements
Merge pull request #84 from opf/feature/rails3_issue-relations-fix

fix for not beeing able to add related issues (#384)