can add reviews programmatically
fixed bug in simulated services
added hashing, fixed ids on simulated cards
removed compiled classes
partway through syncing, stable
can get reviews and cards by id-sets
properly checksums reviews and only syncs when different. still need to do for cards
syncing works at service level, need to add full syncing library
refactored entity getting functions
syncing to get new cards and reviews from server works in simulated environment
cleaned up a bug in services from the refactoring