added handler on js file not found
Merge branch 'master' of https://github.com/ayende/ravendb into RavenDB-2541
- show error when a .js file is missing.
- show error when url doesn't exist and redirect
Merge branch 'master' of https://github.com/ayende/ravendb into RavenDB-2541

Conflicts:
	Raven.Studio.Html5/App/viewmodels/editDocument.ts
Merge pull request #1215 from grisha-kotler/RavenDB-2541

RavenDB-2541 - show errors and redirect on route not existing/availiable