Revert "opentxs: fix -Wtautological-undefined-compare"

This reverts commit 101c9652be73b48fa1f0213470a7fb95c8c3365e.
opentxs: re-fix -Wtautological-undefined-compare
Merge pull request #148 from toxeus/fixWtautological

opentxs: re-fix -Wtautological-undefined-compare
chai: remove obsolete ot_commands.ot
Merge pull request #131 from toxeus/removeChai

chai: remove obsolete ot_commands.ot
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