warnings in ACIP->Tibetan conversion much more configurable. You can
now choose from short or long error messages, for one thing. You can change
the severity of almost all warnings. Each error and warning has an error code.
Errors and warnings are better tested.
The converter GUI has a new checkbox for short messages; the converter
CLI has a new mandatory option for short messages.
I also fixed a bug whereby certain errors were not being appended to the
'errors' StringBuffer.
