cleanup wcwidth() documentation and null behavior
remove verbosity of tests, add skip(), test full scale
brevity regarding assertions, etc.

ignore combining from testing -- too many libc thinks they're width of 1
when python is fully aware that they are combining. also anything
without a name is very likely -1 for wcswidth(3), and for us, although
we may measure it 1 or 2 (correctly), there isnt any point in testing
them.