so throw std::invalid_argument exceptions for these conditions.
Provide a Check method to validate the consistency of a RunStyles and throw
std::runtime_error if corruption is detected.

not remove that run causing iteration over the indicator to hang.

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