Bugfix: Problems in f_utf exposed by unit tests.

Bugfix: Problems in f_utf exposed by unit tests.

The is alphabetic needs to perform the is valid check because its default catch-all is returning F_true.
Ideally at some point (probably distant point) in the future, the literal codes for alphabetic will be matched rather than calling all of the other functions.
In this situation the is valid check can be removed.

Several of the is digit test value assignments are not checking if the value (the pointer) is NULL.

Some of the is word sequences are incorrect.

Add missing f_utf_character_is_alphabetic_numeric().

Fix function name for f_utf_character_is_control_format().

Several is word checks for f_utf_char_t are improperly comparing the entire sequence to an ASCII value when only the first byte should be compared.