Merge pull request #23 from dastrobu/build_with_Swift_5.9

build with Swift 5.9

Merge pull request #21 from dastrobu/swift-5.7

built using swift-5.7

Merge pull request #19 from dastrobu/readme-updates-for-release

add example to README on azimuths computation

bump geodesic to 1.2.0 (#13)

update travis build matrix to use Swift 5.2 (#8)

Added tests for antipodal points which show convergence problems

Testing vs. geodesic package and removed test with gcc on linux due to issues with geodesic. Also added test, where vincenty distance does not converge.

Travis CI setup

fixed some typos