read igrf coefficients broke apexpy

[gregstarr]

Describe the bug
This commit 10358dc broke apexpy. The error happens here:

apexpy/src/fortranapex/igrf.f90

Line 37 in 4fe552e

stop "File open error"

.

I think because it exits with stop, the exit code is 0 and python doesn't interpret it as an error. If you look at the latest CI runs you can see that none of the tests actually run. The problem is that the path depends on the current working directory. If I change my working directory to src/fortranapex then there is no error.

To Reproduce
Steps to reproduce the behavior:

1. build apexpy develop
2. try to create an Apex object

Expected behavior
No error

Screenshots

Computer (please complete the following information):

• OS: Windows 10
• Version develop
• Python version 3.8