Improved protocol message handling.
- now protocol message is decoded only once, instead of decoding it everytime when is used
- command handlers now receive pointers to attachments, instead of raw protocol messages
-Remove cmdBINARY_ATTACHMENT_LOG. Add source command to cmdBINARY_ATTACHMENT.
-Remove cmdDOWNLOAD_TEST use cmdBINARY_ATTACHMENT instead.
-Rename download test to transport test.
-Add source command to binary download stat structure.
-Initial version of cmdBINARY_ATTACHMENT which automatically split files into parts.