Introduce a parser state dictionary.

vmtranslator/translator.py
	-Redefine `translate()`: introduce a local `state` dictionary,
	which is ultimately passed down to `Operation.from_string()`
	and can be modified by some classes' implementations of the
	method.
	-Gets around having to use a global variable hack to generate
	UIDs for `LogicOp` operation labels, and is necessary to pass
	around the current function name for control-flow operations.

vmtranslator/
(parser, operations/(memory, operation, arithmetic_logic)).py
	-Modify functions called by `translator.translate()` to accept
	a `state` argument.