better comments for pairing opcode + subopcode
creating public helper methods for common commands
- created helper methods for changing modes between read UID, read all data, write NDEF message, write previous NDEF Message
- replaced unwieldy setOutputAmplitudeForDeviceWithVolumeCap with a simple properly called deviceHasVolumeCap
- change behavior of deviceHasVolumeCap. no longer checks for max volume or resends config message. it's reasonable to expect that this value will be persisted in local storage and set on app boot. consuming app should handle this process, as well as resending the config message.
- refactored some existing helper methods