Added a skeleton for the api
setup dockerfile for drivethrough
made drivethrough a class instead of a module
drivethrough can now read slices and request them if need be
added factory to drivethrough
Fixed active split image picking raising file not found

Instead, we now raise could not find active split image
implemented blocking pop with timeout

word of warning, it's butt ugly
fixed drivethrough tests to use fancy new abstraction
removed debug prints from slice