Merge pull request #146 from rgommers/fix-readthedocs

BLD: add requirements.txt file for ReadTheDocs build.

util/readthedocs/requirements.txt

@@ -0,0 +1,15 @@
+# Fetch a numpy wheel from the sklearn rackspace wheelhouse.
+# That wheel was generated by @ogrisel by calling `wheel convert` on
+# the binaries from http://www.lfd.uci.edu/~gohlke/pythonlibs/
+# This is a temporary solution. As soon as numpy provides an official
+# wheel for windows we ca delete this --find-links line.
+--find-links http://28daf2247a33ed269873-7b1aad3fab3cc330e1fd9d109892382a.r6.cf2.rackcdn.com
+
+# fix the versions of numpy to force the use of numpy to use the whl
+# of the rackspace folder instead of trying to install from more recent
+# source tarball published on PyPI
+numpy==1.8.1
+Cython==0.20.2
+nose
+wheel
+numpydoc