add feedback to bluetooth exchange

TODO:
 - set id to be a phone number
id is 10 (for phone numbers)
add data default, send hugs after one successful hug

changes:
 - write a default data (Hugginess :) ) if not configured
   => only the ID *must* be explicitly set
 - put the device to sleep when not configured
 - try to send hugs through bt after each successful hug
add resetEEprom and dump all cmd

changes:
  - add a dump_all cmd, which sends the current id and the data
    configured in eeprom
  - add a reset eeprom cmd
  - send an error message if the cmd is invalid/unknown
add a reset cmd + fix bug

 - fix bug: don't hardcode the address in the write function!
 - add a resetEEprom function
use inline definition of simple functions

isFull, isEmpty, etc. are defined in the header.