Added scipy to install_requires

Author: dulalbert

setup.py

@@ -25,6 +25,7 @@ def read(fname):
     license="MIT",
     keywords="gpu optimizers optimization 8-bit quantization compression",
     url="https://github.com/TimDettmers/bitsandbytes",
+    install_requires=['scipy'],
     packages=find_packages(),
     package_data={"": libs},
     long_description=read("README.md"),