Revert "[refs #112] Adding in seek method for compatability with requests 1.2.0"

This reverts commit 25885590900dbcad490d14c983b39f28167cbee4.

Part of this work was already done, and does not make sense to keep this approach.
Revert "Adding a wrapper around the file-like objects used in github3 due the changes in requests [refs #112]"

This reverts commit 9109400325bf72a871cdec2a5767c2f5b2a6790c.

Part of this work was already done, and this approach is not really valid any more