allow resources to be resolved by dialog again

This re-enables the ability to pass objects through to the dialog via resolve, as currently only strings (sets the value) or functions (gets invoked) work. Anything that isn't a string is currently treated as a function and invoked.

It was stopped by https://github.com/angular-ui/bootstrap/commit/739f86f21a2919654bcb01f3edc6ddeeb1b35c22#L0L220
but I don't know whether that was by design or oversight?