========== Notes from Doug ==============
I think we should:
1) retain the current values that we have now. This eases use of the binary ICU
data, which we need to stay in synch with, and keeps our code efficient.
2) add the enum values to UCharacter, and deprecate UCharacterProperty, to
lessen the liklihood that people will use Character constants with UCharacter
3) clearly document the fact that our enum values have no gaps, unlike the
java.lang.Character values, so that people using the values for their own data
are aware of the issue.
We can add the documentation (to UCharacter and perhaps UCharacterProperty) now.
The new values (and recoding to not use UCharacterProperty) we can schedule for