fixed up serialization/deserialization issues, etended daos

so the user and topic daos now have all the methods they need, and those
methods actually work! i've also fleshed out MeApi to use these methods,
which involved fixing up some serialization and deserialization issues.

also started writing out the tests needed for the MeApi.

next steps:
- start fleshing out topic api
- interface for event api
- interface for requests api
- mocking for both
- tests for user and topic apis