Changes in version 0.99.4 (2020-11-11)
+ Added additional checks to results of queries
+ Added informative messages to failed requests

Changes in version 0.99.3 (2020-10-24)
+ Added link to OpenSky website in DESCRIPTION

Changes in version 0.99.0 (2020-10-14)
+ First version
+ Submitted to CRAN
