Fixed headers and attachment migration for SMTP Dispatcher properties.
Added getElement() to DonkeyElement.
Issue: MIRTH-2607
MIRTH-2676, MIRTH-2552: Changed the default channel writer response timeout to zero. Also, set the queue to be "Always" in the response channel writers that are being created for connectors that use "Send response to".
Fixed Wait for Channel Response not being properly migrated. If it is set to false now, the destination queue will be enabled.

When creating a response channel writer, just use the "synchronised" element now to determine the destination queue instead of adding "usePersistentQueues".
Issue: MIRTH-2676
MIRTH-2365: Fixed bug that caused only the first message in the queue to have its sent properties generated and stored. Before, subsequent messages in the queue did not have sent content stored, so it was possible to send a previously queued message using the *new* connector properties. Now since the sent data is always being stored beforehand that won't happen.
HTTP Listener: response headers are now being migrated.
HTTP Sender: query parameters and headers are now being migrated.
Issue: MIRTH-2603
Migrate velocity references in connector properties that could have used the following references.

${MESSAGEATTACH} -> ${message.encodedData}
${ORIGINALNAME} -> ${originalFilename}
Issue: MIRTH-2679
Fixed the ER7BatchAdaptor using the wrong delimiter pattern.
Issue: MIRTH-2680
Added property for HL7v2 data type "convertLineBreaks". If set to true, all line breaks of CRLF, CR, LF will be converted to the segment delimiter.
The segment delimiter property in serialization properties no longer takes in multiple values seperated by "|". It now only takes in literal sequences.

Created an optimized method in StringUtil to perform line break conversion.
Updated reader, auto responder, and response validators to match the property changes.

Updated ImportConverter3_0_0 to match the property changes.

Using Apache Commons StringUtils methods where appropriate for increased performance.
Issue: MIRTH-2672