message: add info about new board
diff: @@ -27,6 +27,7 @@ To create an instance of BoardShim class for your board check required inputs in
  "GforcePro", "BoardIds.GFORCE_PRO_BOARD (16)", "-", "-", "-", "-", "-", "-", "-", "-", "-"
  "FreeEEG32", "BoardIds.FREEEEG32_BOARD (17)", "dongle serial port", "-", "-", "-", "-", "-", "-", "-", "-"
  "BrainBitBLED", "BoardIds.BRAINBIT_BLED_BOARD (18)", "dongle serial port", "Optional: MAC address", "-", "-", "-", "-", "-", "-", "-"
  + "GforceDual", "BoardIds.GFORCE_DUAL_BOARD (19)", "-", "-", "-", "-", "-", "-", "-", "-", "-"
  Playback File Board
  @@ -557,8 +558,27 @@ Supported platforms:
  Board Spec:
  - num emg channels: 8
  +- sampling rate: 650
  +
  +gForceDual ArmBand
  +~~~~~~~~~~~~~~~~~~~
  +
  +`OYMotion website <http://www.oymotion.com/en>`_
  +
  +To choose this board in BoardShim constructor please specify:
  +
  +- board_id: 19
  +
  +Supported platforms:
  +
  +- Windows
  +
  +*Note: Unlike other boards it returns ADC value instead uV.*
  +
  +Board Spec:
  +
  +- num emg channels: 2
  - sampling rate: 500
  -- communication: FTDI
  FreeEEG32
  ----------
  