Cache presence of '<' in entities content

slightly modify how ent->checked is used, and use the lowest bit to
keep the information
diff --git a/SAX2.c b/SAX2.c
index ce7a5d6..c7ecd7f 100644
--- a/SAX2.c
+++ b/SAX2.c
@@ -605,7 +605,9 @@
 	}
 	ret->owner = 1;
 	if (ret->checked == 0) {
-	    ret->checked = ctxt->nbentities - oldnbent + 1;
+	    ret->checked = (ctxt->nbentities - oldnbent + 1) * 2;
+	    if ((ret->content != NULL) && (xmlStrchr(ret->content, '<')))
+	        ret->checked |= 1;
 	}
     }
     return(ret);