Added tests to cover userStyle.

fixed a bug in userStyle where it would not process data that was false.
process will do this, so I made userStyle do it as well by adding
in a definedness check on $output.

lib/WebGUI/Session/Style.pm

@@ -423,7 +423,7 @@ sub userStyle {
 	my $self = shift;
         my $output = shift;
 	$self->session->http->setCacheControl("none");
-        if ($output) {
+        if (defined $output) {
                 return $self->process($output,$self->session->setting->get("userFunctionStyleId"));
         } else {
                 return undef;