make setup_orekit_data more robust
Fixes #1 (closed):
- Adds two unit tests for the case that the
orekitdata
library is not present - Adds a default value to the
filenames
argument insetup_orekit_data
(orekit-data.zip
), and adds a check forfilename
beingNone
insetup_orekit_curdir
- Adds a test step in the gitlab CI to run PyhelpersTest.py twice, without and then with the
orekitdata
library installed