Defer destroying arrays.
Change tile allocation to adjust for the number of workers, rather
than a fixed constant.
Ensure worker context is available after initialization.
Parakeet updates.

Add import statements to the prelude of generated code for any modules
called.

Cache generated files in a known location.

Add option to call out to CUDA.
Fix integer indexing.  Use user-specified dtype for ones/zeros.
Fix selection of integer indices.
Start working towards multi-type tiles.
Minor naming changes.

Prepend configuration file options so that flags take precendence.

Fix test for number of workers required in a cluster.