Undeprecate Factory...

The problem is with BaseVarInit; it implements this interface, and an ASM
instruction is generated for Vars to produce a value.

As such, Supplier is in fact not usable in this context since its method,
.get(), conflicts with that of Reference, which Var inherits. Attempting to
replace Factory with Supplier generates an AbstractMethodError at runtime...
Factory: add comments
VarInitClassGenerator: fix gross error in bytecode...

Wrong signature!
Var: get back to initialize with a Factory