Merge pull request #182 from hintjens/master

Merge conflicts
Merge pull request #183 from hintjens/master

Added support for libsodium to Travis builds
add travis ci build image to readme
Merge pull request #184 from felipecruz/feature/readme_travis_status

add travis ci build image to readme
ZPL name parsing was not accurate
Trivial code cleanup
Finished zcurve first implementation and test cases
Renamed zconfig _set methods for consistency