fix spurious punct class for some surrogate codepoints (invalid)

this happened due to their entries in UnicodeData.txt

destubify iswalpha and update iswpunct to unicode 6.1

alpha is defined as unicode property "Alphabetic" plus category Nd
minus ASCII digits minus 2 special-cased Thai punctuation marks
supposedly misclassified by Unicode as letters.

punct is defined as all of unicode except control, alphanumeric, and
space characters.

the tables were generated by a simple tool based on the code posted
previously to the mailing list. in the future, this and other code
used for maintaining locale/iconv/i18n data will be published either
in the main source repository or in a separate locale data generation
repository.