Improve resource loading on backlog.
Improve resource loading on taskboard.
Improve resource loading on userstory detail.
Improve resource loading on issues detail.
Improve resource loading on issues list.
Improve resource loading on kanban.
Improve resource loading on wiki.
Fix error page url resolution.

Now it properly redirects to error page when
api service is down.
Merge pull request #9 from taigaio/parallel-loading

Improvements on resource loading.