Rename genxpm.awk -> unix-gen-xpm.awk and genres.awk -> unix-gen-res.awk

to follow current naming conventions.

Originally committed to SVN as r2566.

autogen.sh

@@ -285,7 +285,7 @@ touch ${srcdir}/aegisub/posix/config.h
 
 echo "--- Converting BMP resource files -> XPM ---"
 # BMP -> XPM via src/res.rc
-cat ${srcdir}/aegisub/res.rc | ${BIN_AWK} -f ${srcdir}/scripts/genxpm.awk BIN_CONVERT="$BIN_CONVERT" > ${srcdir}/aegisub/bitmaps/Makefile.bitmaps
+cat ${srcdir}/aegisub/res.rc | ${BIN_AWK} -f ${srcdir}/scripts/unix-gen-xpm.awk BIN_CONVERT="$BIN_CONVERT" > ${srcdir}/aegisub/bitmaps/Makefile.bitmaps
 cd ${srcdir}/aegisub/bitmaps
 make -f Makefile.bitmaps
 cd ${srcdir}