SpringSource/spring-integration — pull request #619 by olegz (2012-09-12 08:04:49+00:00)
Title: INT-1819 Mail pseudo-tx support

Added pseudo-tx support for Mail inbound adapters
For polling adapters no changes have been made other then returning a javax.mail.Message instead of its copy so
post-tx dispositions could be performed on it.
For Imap IDLE adapter changes are simiar to the once present in SPCA where TX synchronization logic was added to ImapIdleChannelAdapter
Couple of things to note:
First IDLE receives an array of messages while Polling task receives one message which means i need to sendMessage in the Polling task in the separate thread, so for maintaining single thread semantics we have now it uses single thread executor to send Messages
Renamed MSRH to TransactionalResourceHolder since we no longer use 'source' anywhere and in the case of IDLE there is no MessageSource. Its is truly a holder of attributes we want to make available for use (e.g., SpEL)