memory model

[scott-cotton]

• constraints (load, store, transfer)
• plain serialize
• integrate types. memory model currently uses go/types and should use typeset instead.
• solve
• solve with opaque bindings
• export
• import

[scott-cotton]

commit 991f7a5 makes progress on integrating types. Just need to remove the old path once the new is connected up the stack.

[scott-cotton]

commit bcbf71a integrates pal typesets (still a bit of stabilisation, but basically ok for the task).