repair broken tests

[corviday]

This PR fixes two tests which broke due to changes in the ways underlying system libraries work:

1. A test of reprojecting coordinates from one system to another stopped working when the proj4 library no longer did an automatic units conversion; the units have to be manually fixed. @QSparks tracked this down
2. A test of writing to a netCDF file began failing with system library netCDF 4.9.1 . As of this version of the netCDF system library, if you change a variable's _FillValue by assigning a value to the attribute with the same name, and then write to the variable, the write will crash.

Resolves #11

[corviday]

Draft until:

• it can be uploaded to CRAN (depends on PCICt)
• tests can be fixed