Use url resolver to lookup import paths rather than deferring to native vscode behavior

[jaichandra]

cmd+click doesn't work on below import as the path is not a real path pointing to bower_components folder. <link rel="import" href="../polymer/polymer.html">

[rictic]

CMD click on an href is a native behavior of the editor I think, but we may be able to customize it here.

[abdonrd]

Any progress here? Thanks in advance!