INT-2744 Mechanism to Suppress Standard Headers

Currently, HTTP mappers don't know if they are inbound
or outbound. This causes problems with mapping certain
headers.

For example, on an inbound adapter, a mapped Content-Length
header should not be re-mapped to an HTTP Header during
response header mapping. However, the Content-Length
does need to be mapped on an outbound adapter response.

Introduce the notion of an exclusion list for both
request and response standard headers.

If a mapper has been configured to use standard headers,
we can detect whether the mapper is being used for inbound
or outbound mapping. We can then apply an 'exclusion' for
certain headers.

Currently, no request headers are suppressed on outbound
mappers and only the 'Content-Length' response header
is suppressed on inbound mappers.

The default mappers created via the static factory
methods use these defaults. Exposing the exclusion setters
will allow users to suppress additional headers, if
deemed necessary.
Merge pull request #618 from garyrussell/INT-2744

* garyrussell-INT-2744:
  INT-2744 Mechanism to Suppress Standard Headers
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)

INT-1819 Polishing

- Change TransactionalResourceHolder to IntegrationResourceHolder
- Make messageSource available as an attribute
- Allow configuration of Executor for ImapIdle adapter
- Add parser test for TX ImapIdle adapter
- Fix bundlor config for mail
- Remove top level <transactional/> element that was added to core
- Restore 'legacy' mail attributes in TX, and add schema doc

INT-1819 Mail TX Reference Docs

Add reference documentation for mail transaction support.

INT-1819 Remove 'public abstract' from interface

Modifiers are not needed on an interface.
Merge pull request #622 from olegz/INT-1819

* INT-1819:
  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)
INT-2749 add'long' cast to SftpFileInfo

Add cast to (long) to a return value of getMTime methood called in SftpFileInfo.getModified()
Merge pull request #630 from olegz/INT-2749