Hack24 sparse

[garrettwrong]

This cleans up my portions of the work accomplished and todo items from the first hackathon pass.

• Resolves downsample/crop_pad issue that was found during first day.
• Adds cusparse methods currently used in ASPIRE (with smoke test) via sparse wrapper hooked onto numeric config.
• Adds dct and idct methods to fft wrappers. These are switched via the fft backend config.
• Replace sparse and i/dct methods in FLE with those from our numeric module.
• Refactor FLE code towards using xp methods for evaluate_t and evaluate.
• Implements the memory cleanup workaround.

[j-c-c]

Looks good!