Clean up example_data folder

[MichaelCurrie]

I find it the [example_data folder] on Google Drive confusing because:

• Some of the .mat files apparently cannot be opened by HDFView, which apparently means they aren’t stored in HDF5 format. Is this the case for the old Schafer lab files?
• It’s not clear from the names which files are generated by the Schafer lab binary and which are generated by our new process
• The WT2 Binary seems to require that in addition to the .avi file there is also a metadata file or files colocated in the same directory for the processing to proceed. I’m not sure where those files are, here.

[MichaelCurrie]

This hasn't caused any issues and so I think we'll leave this as a wontfix.