message: add info about get_board_descr to docs
diff: @@ -18,7 +18,6 @@ You can compare BrainFlow's timestamp with time returned by code like this:
  import time
  print (time.time ())
  -
  Generic Format Description
  ----------------------------
  @@ -52,6 +51,43 @@ Exact format for this array is board specific. To keep the API uniform, we have
  Using the methods above, you can write completely board agnostic code and switch boards using a single parameter! Even if you have only one board using these methods you can easily switch to dummy BrainFlow boards and it will help you during developemnent and testing.
  +Getting All Info About Device And Supported Channels
  +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  +
  +There is a method :code:`get_board_descr(int board_id)`. You can use it to get all info about specified device and BrainFlow channels for this board.
  +
  +.. code-block:: python
  +
  + from pprint import pprint
  +
  + import brainflow
  + from brainflow.board_shim import BoardShim, BoardIds
  +
  + board_id = BoardIds.SYNTHETIC_BOARD.value
  + pprint(BoardShim.get_board_descr(board_id))
  +
  +.. code-block:: json
  +
  + {"accel_channels": [17, 18, 19],
  + "battery_channel": 29,
  + "ecg_channels": [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16],
  + "eda_channels": [23],
  + "eeg_channels": [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16],
  + "eeg_names": "Fz,C3,Cz,C4,Pz,PO7,Oz,PO8,F5,F7,F3,F1,F2,F4,F6,F8",
  + "emg_channels": [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16],
  + "eog_channels": [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16],
  + "gyro_channels": [20, 21, 22],
  + "marker_channel": 31,
  + "name": "Synthetic",
  + "num_rows": 32,
  + "package_num_channel": 0,
  + "ppg_channels": [24, 25],
  + "resistance_channels": [27, 28],
  + "sampling_rate": 250,
  + "temperature_channels": [26],
  + "timestamp_channel": 30}
  +
  +
  Other Channels
  ----------------
  