add SCI_GETWORDCHARS(<unused>, stringresult chars) command to get word chars
add SCI_GETWHITESPACECHARS(<unused>, stringresult chars) to get whitespace chars
add SCI_GETPUNCTUATIONCHARS(<unused>, stringresult chars) to get punctutation
also add tests for {Set,Get}{Word,Whitespce,Punctuation}Chars, CharClassifier