add pybedtools req. for docs

setup.py

-# from setuptools import setup
-# 
-# setup(
-#     name='bedtools',
-#     install_requires=["numpy>=1.6.0", "matplotlib>=1.1.0"],
-#     )
+from setuptools import setup
+
+setup(
+    name='bedtools',
+    install_requires=["pybedtools"],
+    )