Merge pull request #55 from eile/master

Ignore MacPorts errors during port-get
Bump Boost version to 1.55, no tclap build on Windows
Merge pull request #56 from tribal-tec/master

Bump Boost version to 1.55, no tclap build on Windows
Merge pull request #57 from eile/master

Integrate common CMake stuff using git externals, create BY Coverage target
Add doxygen to default install targets