More generic collections as function parameters in PublicApi.
Refactored PrivateApi request code.
Consistent use of Long for timestamps.
`type` -> tpe
Added test-app, refactored public api a bit.
Further refactoring of public api.
Refactored protocol/formats.
Renamed Error to ErrorParser.
Added fee api, renamed ErrorParser case class to Error.
Info api, fee api for one pair.