Add operations sub-package.

vmtranslator/
(operation.py -> operations/(__init__, arithmetic_logic, operation).py)
	-Convert the `operation` module to an `operations` sub-package.
	-Break it up into an `operations.operation` module, which
	contains the base `Operation` class, and
	`operations.arithmetic_logic`, which contains all
	arithmetic/logic classes (`BinaryOp`, `UnaryOp`, etc).