Expanded examples and configuration info
Changed defaults

  - declare btSerial so that this library works more like
    the hardware and software serial libraries. The btSerial class must
    be instanciated in the sketch and btSerial.findbaud() called to
    initialize the port.

  - Changed to use a software serial port built from pins A2-A5.
  - Debug output is enabled in HC05.h and must be initialized in the
    sketch.