Fixes Bug 938880, added top of tree link
Fix Bug 940406, ensure JSON is always returned for Ajax request to avoid parse errors
Fix bug 938884, restore nav panel on file view
Fine tuning the panel
Merge branch 'bug938880-add-top-of-tree-link-above-results' into ui

Conflicts:
	dxr/static/js/dxr.js
	dxr/templates/layout.html
Merge pull request #205 from ossreleasefeed/bug938884-restore-nav

Bug938884 restore nav and always return JSON for Ajax calls.