Allow objects to input data into EdfReader

[hahnicity]

Currently working on AWS with EDF objects. Making a feature request to allow some kind of objects similar to StringIO or urllib3.HTTPResponse for input into the EdfReader class instead of a filename. Presumably, this could work using a .read() call on the object. This would save on some IO so that objects wouldn't have to be directly written to local disk before reading and could instead stay remote based.

[skjerns]

This is probably not so easily possible, as the library we wrap (edflib) is written in C and works with strings that point to files on the file system. Unfortunately we cannot easily pass FILE objects or streams to it, and the last time I tried to implement that I didn't get further (See also #102 and #100). It would probably be possible somehow, but would need some adaptation of the C code to work with streams.

If you feel comfortable enough in C to work on something like this let me know!
Else I have to unfortunately put this on the backend, as I don't have enough time right now do work on this.