support BEX bits mnemonics in Things fields
add parser for [PARS] sections in BEX files
add parser for [CODEPTR] sections in BEX files
clean-up in doom/deh_bexpars.c
explicitely scan for DECIMAL numbers

or else numbers like the 09 in entries like "par 09 120" are interpreted as octal and are thus considerd invalid.
add parser for INCLUDE directives in BEX files
add portable pendant to libgen.h's basename()
Merge branch 'master' into bex
add portable pendant to libgen.h's dirname()
use M_DirName() in LoadNerveWad()
Merge branch 'master' into bex
use M_DirName() in doom/deh_bexincl.c