Merge pull request #8 from fvalenza/master

.gitmodules

.travis

.travis-yml

.travis.yml

README.md

benchmark/timings.cpp

src/CMakeLists.txt

src/algorithm/center-of-mass.hpp

src/multibody/joint/joint-spherical-ZYX.hpp

src/multibody/joint/joint-spherical.hpp

travis_custom/custom_before_install

travis_custom/custom_build

unittest/CMakeLists.txt

unittest/cholesky.cpp

unittest/com.cpp

unittest/jacobian.cpp

unittest/joints.cpp