add stub email canonicalizer

Added a stub function to stand in for eventual email canonicalizer.

darcs-hash:20080517172110-84dde-d2c83cb5e88693100c444b0ed088eed327f8a77d.gz

lib/common.php

@@ -236,6 +236,13 @@ function common_canonical_nickname($nickname) {
 	return strtolower($nickname);
 }
 
+# get canonical version of email for comparison
+function common_canonical_email($email) {
+	# XXX: canonicalize UTF-8
+	# XXX: lcase the domain part
+	return $email;
+}
+
 function common_render_content($text) {
 	# XXX: @ messages
 	# XXX: # tags