rename GT_UNDEF_ULONG -> GT_UNDEF_UWORD

also make scgt does not report any errors
rename GT_UNDEF_LONG -> GT_UNDEF_WORD
re add deprecated defines
update documentation and clean up src_check errors
rename GT_LU -> GT_WU etc

closes #106
closes #91
update documentation
Merge pull request #123 from Garonenur/undef

Undef