Add warning message in catalyst_stub.h -- catalyst_stub_initialize() to let user know that the stub implementation is being used
A warning message should be add in to catalyst_stub.h in the catalyst_stub_initilize() method to let users know that the stub implementation is being used instead of being replaced with the actual, likely intended, implementation of Catalyst. Also, directions should be added in there as to how to run with a full implementation instead of the stub implementation.