Better error reporting on invalid class generation

[teslacoil]

I had an xml file with:

android:id="@+android:id/icon"

and a -v17 with

android:id="@android:id/icon"

Obviously the inconsistent + is not needed and wrong, but it didn't cause any issues without using Holdr. I think it's completely reasonable for Holdr to be stricter about something like that, however the error message was not helpful.

> trying to create the same field twice: icon

Without letting me know which layout xml caused the problem. I hacked in a "creating Holdr_XXX.java" line before the "created Holdr_XXX.java" to assist in finding the issue, but it'd be great to have something officially in Holdr.

[evant]

Totally agree, there are a few places which could use improved error reporting.