added 'abort' & QSE_AWK_ABORT to awk.

added a new sed command 'C' that resembles the cut utility
dropped the cut utility.
added qse_str_nrcat()/qse_mbs_nrcat()/qse_wcs_nrcat()

qse/lib/awk/tree.h

@@ -273,6 +273,7 @@ struct qse_awk_nde_exit_t
 {
 	QSE_AWK_NDE_HDR;
 	qse_awk_nde_t* val; /* optional (no exit code if QSE_NULL) */
+	int abort;
 };
 
 /* QSE_AWK_NDE_NEXT */