This patch adds user invitations, a way for existing users on a site

to send an email to their friends and invite them to create an account
on the site.  The feature is enabled or disabled in the site Settings.
(Operation/Settings.pm)

It is implemented as a new operation, Invite (Operation/Invite.pm,
Help/Invite.pm, i18n/English/Invite.pm), and the option is displayed
as an option on the user's account screen. (Operation/Shared.pm).
The form is templated, and lives in the Invite namespace.  Once
the invitation is submitted, if the user's email address is not
already in WebGUI, an email is sent and a record is stored in
the userInvitations table.

When the friend gets the invitation, they are taken to the account
creation screen, which conveniently has their email address already
filled in.  This required changes in the Auth modules (Auth.pm, Auth/*.pm),
and ProfileField.pm.  The latter was so that profile fields can have
their values manually set.  The former changes handle inserting the
email address, bypassing the anonymous registration check, and
updating the record in ther userInvitations table.

I refactored some code out of the AdminConsole for finding the url
back to the site and added it to Session/Url.pm.  The method is
called getBackToSiteUrl.

lib/WebGUI/Help/Invite.pm

@@ -0,0 +1,54 @@
+package WebGUI::Help::Invite;
+
+our $HELP = {
+
+	'invite form template' => {
+		title => 'invite form template title',
+		body => 'invite form template body',
+		variables => [
+			{
+				name     => 'inviteFormError',
+                required => 1,
+			}, 
+			{
+				name     => 'formHeader',
+                required => 1,
+			}, 
+			{
+				name => 'formFooter',
+                required => 1,
+			}, 
+			{
+				name => 'title',
+			}, 
+			{
+				name => 'emailAddressLabel',
+			}, 
+			{
+				name => 'emailAddressForm',
+			}, 
+			{
+				name => 'subjectLabel',
+			}, 
+			{
+				name => 'subjectForm',
+			}, 
+			{
+				name => 'messageLabel',
+			}, 
+			{
+				name => 'messageForm',
+			}, 
+			{
+				name => 'submitButton',
+			}, 
+		],
+		fields => [
+		],
+		related => [
+		]
+	},
+
+};
+
+1;  ##All perl modules must return true