syncbase: Relax restrictions on wire.Id Name.

Relaxed restrictions on wire.Id Name component to allow up to 1024 byte
(previously 64 byte), arbitrary Unicode (previously C identifier) names,
excluding only Unicode control characters (notably including \0 and \n).

Added restriction on blessings (in general, not just Id blessings) and
row keys to also exclude Unicode control characters.

Also cleaned up key splitting helper usage.

MultiPart: 3/3
Change-Id: Ic3842e21f5c7187a3b6b13246d961b72169fc8e5
1 file changed