Event: Empty namespaces should be uneventfully ignored

Thanks @hamishdickson for the report!

Closes gh-1769
(cherry picked from commit 8653068dd6b8a515f5c1d8a0fda4479e9534103e)

src/event.js

@@ -14,7 +14,7 @@ var rformElems = /^(?:input|select|textarea)$/i,
 	rkeyEvent = /^key/,
 	rmouseEvent = /^(?:mouse|pointer|contextmenu)|click/,
 	rfocusMorph = /^(?:focusinfocus|focusoutblur)$/,
-	rtypenamespace = /^([^.]*)(?:\.(.+)|)$/;
+	rtypenamespace = /^([^.]*)(?:\.(.+)|)/;
 
 function returnTrue() {
 	return true;

test/unit/event.js

@@ -587,6 +587,17 @@ test("namespace-only event binding is a no-op", function(){
 		.off("whoops");
 });
 
+test("Empty namespace is ignored", function(){
+	expect( 1 );
+
+	jQuery("#firstp")
+		.on( "meow.", function( e ) {
+			equal( e.namespace, "", "triggered a namespace-less meow event" );
+		})
+		.trigger("meow.")
+		.off("meow.");
+});
+
 test("on(), with same function", function() {
 	expect(2);