Comment cleanup.
Moved out TransportCallback into own files.
Hide Pid in source file.
Removed commented out code.
Moved header back to include because it is on public API.
Removed virtual - not needed.
Removed virtual - not needed.
Encapsulation of member variable.
Merge pull request #156 from murrekatt/client_cleanup

More client cleanup
Generate Doxygen into build directory.
Merge pull request #165 from murrekatt/doxygen

Generate Doxygen into build directory.
Removed old release notes. Maybe we should move that into the ChaneLog file?
Removed security comments.
OpenTransactions: remove ZMQ2 artifacts
Merge pull request #164 from murrekatt/develop

Removed some files in docs
Merge pull request #166 from toxeus/removeZMQ2

OpenTransactions: remove ZMQ2 artifacts
Made member functions const where possible in OTAxxx.hpp thru OTCxxx.hpp