Release GIL

[mrocklin]

Should this library safely release the GIL around compress and decompress calls? This would allow the use of this library in parallel on multiple cores within a single process.

https://www.safaribooksonline.com/library/view/python-cookbook-3rd/9781449357337/ch15s07.html

[mrocklin]

Oh, I see that this has already been implemented in #45

[jonathanunderwood]

https://github.com/python-lz4/python-lz4 is the new project page, with many new updates to functionality, including an implementation of the LZ4 frame standard.