support BytesIO input

[JackNelson]

Current state requires there to be an actual file on the local machine, which isn't always the case if the file resides in remote cloud storage (i.e. an S3 bucket). Accepting a BytesIO object would allow one to wrap S3 bucket files for parsing. Would remove requirement to save the file to disk on the local machine before parsing.

[seimit]

Hi Jack,
I think this is reasonable request.
Not sure when I will have time to implement it, because I'm currently busy with the STIL library.
Anyway I will assign to me and later will be implemented.
Regards,
Seimit