definition of $result is too far away, 1 is more clear
support customized forward message and use scrip to send forwarded message

now we record the forward transaction with customized message and use a scrip
bound to it to actually send the message.
(SendForward action is newly added for it)
Only add the default "This is a forward..." if no content is supplied
Allow forwarding to set the subject
upgrade content for new customized forward messages
update tests to reflect new subject changes

subject tag is always prefixed(even before "Fwd:") now.
document "Forward" and "Forward Ticket" templates updates
Merge branch '4.2/forward-with-message'