Now checks memory operations and function call argument types.

Type inferer and predefined entities are no longer single objects.  They
can be instantiated like other classes.

An SSA variable now has an `inferred type` field which represents its
type.  The type is filled in when loading a bundle, and can be dependedn
on during execution.

Added stricter static checking related to variable types.

Moved CanBeIntegerized to its own package.

Removed "Word" from TypeSizes and uniformly import from uvm.refimpl.

Now MicroVM runs the static analyzer when adding any bundles.