Support data that is not a numpy array

[jhueckelheim]

The checkpoint storage in pyrevolve is a big numpy array, and the "pointers" that are given to checkpoint.save(ptr) and checkpoint.load(ptr) are in fact slices of that numpy array. A user who needs to store data that is not numpy will be out of luck. Not sure if this is really a problem in need of a fix, unless someone wants to do mixed-precision computing or checkpoint non-floating-point data. Open for discussion.

[navjotk]

I believe we have addressed this in the latest release since the compressed data is no longer a numpy array.