add CI badges

Author: simonbyrne

README.md

@@ -1 +1,4 @@
 # EnsembleKalmanInversion.jl
+
+[![Travis Build Status](https://travis-ci.org/climate-machine/EnsembleKalmanInversion.jl.svg?branch=master)](https://travis-ci.org/climate-machine/EnsembleKalmanInversion.jl)
+[![Appveyor Build Status](https://ci.appveyor.com/api/projects/status/s7l958ngcd3efv9t/branch/master?svg=true)](https://ci.appveyor.com/project/simonbyrne/ensemblekalmaninversion-jl/branch/master)