Merge pull request #323 from benma/processserverreply

Break up OTClient::ProcessServerReply
Moved duplicate code into new function OTClient::setRecentHash.
Extend OTClient::setRecentHash to refactor more duplicate code.
Use shared_ptr for OTMessage to fix a memory leak.

A unique_ptr can be used instead as soon as some implementation details
of OTCLient/MessageBuffer are fixed.