cmake, SWIG: Minimum 3.0.0
INSTALL-Docs: Requires SWIG >=3.0.0
Merge pull request #20 from lclc/swigMinimum

Swig minimum 3.0.0 cmake check & docs update
CMake: fix protobuf include path on OS X

include_directories() should be executed for all platforms.
find_package(Protobuf) can be removed since it's executed in the
top-level CMakeLists.txt.
Merge pull request #22 from toxeus/fixMacCompile

CMake: fix protobuf include path on OS X
cppcheck: fix variableScope
Merge pull request #21 from toxeus/fixScope

cppcheck: fix variableScope
Some anyoption related changes:
- Added AnyOption::findOption
- Moved anyoption.cpp to api lib
- Replaced #include <anyoption.hpp> in opentxs.hpp with class AnyOption;
- Changed #include <anyoption.hpp> to #include <anyoption/anyoption.hpp>
  to remove specific dependency_include_dir
Some renaming and reordering of standard arguments in opentxs.cpp
Switch to stream logging in opentxs.cpp
One class per opentx command
Moved most of ot_commands_ot.cpp to correct CmdXxx.cpp