Warn when an optimized build doesn't set NDEBUG and then #define it ourselves -- unless the build explicitly sets DEBUG.

Require a colon before 'group' or 'union' except for unnamed unions as well as the legacy case of a named union with an ordinal (where the colon is optional).

Remove some function prototypes that apparently aren't needed and apparently tickle a bug in Clang trunk.

New method isFoo() exists for union fields only and returns true if foo is the active union field.