More thoughtful try/except when import fails

[jGaboardi]

Following #271, and other similar corrupted install issues in the past, it may be an opportune time to rethink the current implementations of @requires, simport, and the various cases to skip geopandas-based functionality during unittests (i.e., libpysal, spaghetti, etc...). The jit decorator may also benefit from a more specific try/except.

See the original comment here

Our SKIPIF check sets geopandas to not be available on ImportError, but does not check the specific message that is thrown. Maybe a ModuleNotFoundError would be more appropriate for the unavailability of geopandas, where ImportError is reserved for an actual problem with the install?