Handle unmodified left left click only, allow open-in-new tab etc. to use the default handler.
Added tests for shift/ctrl/meta/middle-clicked uiSrefs.
Merge pull request #275 from Demeterr/master

Only handle unmodified left left click in uiSref
HTML5-mode compatibility + tests, fixes #276
 - Refactoring directive test event handling
Fixes #257