Added better drawing load failure handling

Added better drawing load failure handling

Failure of loading drawings will now close the drawing view and show an
error message, hinting at file or permission issues, instead of leaving
the user facing a continuosly loading interface.

Adds test to cover.

This also updates errors from our HTTP service to be wrapped in a custom
error type for better identification and so the error is an actual
javascript error. Should be object compatible.

Related to #3955.