grouped some files into subfolders to reduce mess

--HG--
rename : GOnpp/AutoCompletion.cpp => GOnpp/AutoCompletion/AutoCompletion.cpp
rename : GOnpp/AutoCompletion.h => GOnpp/AutoCompletion/AutoCompletion.h
rename : GOnpp/WcharMbcsConverter.cpp => GOnpp/StringUtils/WcharMbcsConverter.cpp
rename : GOnpp/WcharMbcsConverter.h => GOnpp/StringUtils/WcharMbcsConverter.h
rename : GOnpp/tokens.h => GOnpp/StringUtils/tokens.h
rename : GOnpp/tstring.cpp => GOnpp/StringUtils/tstring.cpp
rename : GOnpp/tstring.h => GOnpp/StringUtils/tstring.h