Support playback for BrainFlow data files

[philippitts]

Is your feature request related to a problem? Please describe.

Both the OpenBCI GUI and BrainFlow have the ability to record data to a file. However, these two systems record the data in slightly different formats. Currently it is possible to playback files recorded in the OpenBCI GUI format. It would be useful to have a way of also playing back BrainFlow data files for OpenBCI devices.

Describe the solution you'd like

The ability to load and playback data recorded in the BrainFlow file format.

Describe alternatives you've considered

Another option could be create a utility to convert BrainFlow files to the OpenBCI file format. However, this would involve extra steps for the user.