Set cache=True in jit_module

[aperezhortal]

Hi @vlouf,

Currently, numba compiles the modules each time that they are imported. This adds a few seconds to the total computation time that can be saved by adding cache=True to the jit_module directives.

I've tested this in my current setup processing nexrad data and worked out of the box.

If you like the idea of adding the cache, I can prepare a PR with the changes.

[vlouf]

Hi @aperezhortal

Thanks, that's a great idea! Yes please do a PR.

[vlouf]

Commit 8b193e4