Apparently massive reduction in memory usage.

Instead of saving the metadata, it just saves the bytecode and disassembles them
on load.
Got the memory usage down again.

Metadata is no longer stored, it is only used during evaluation. Everything else
is stored as a strict ByteString. It looks like generate might be the last
bastion of leaky memory.
Got rid of another high retainer
I think that's enough optimizations for now.

Should be sufficiently optimized to gather libraries of the size required for
many variable programs.