Added requirements for requires.io [skip ci]

Author: Chilipp

docs/requirements.txt

@@ -1,3 +1,3 @@
 # Sphinx
 #   https://github.com/sphinx-doc/sphinx/blob/master/CHANGES
-sphinx==1.5.2 # rq.filter: >=1.3, <1.6
+sphinx==1.6.3 # rq.filter: >=1.3, <1.7

requirements.txt

@@ -0,0 +1,17 @@
+# Matplotlib
+#   https://github.com/matplotlib/matplotlib/blob/master/CHANGELOG
+matplotlib==2.0.2  # rq.filter: >=1.4,<2.1
+
+# xarray
+#   https://github.com/pydata/xarray/blob/stable/doc/whats-new.rst
+xarray==0.9.6  # rq.filter: >=0.7.0,<1.0
+
+# pandas
+#   http://pandas.pydata.org/pandas-docs/stable/whatsnew.html
+pandas==0.20.3 # rq.filter: >= 0.18.0,<0.21
+
+# scipy
+scipy==0.19.1 # rq.filter: >=0.18,<0.20
+
+# statsmodels
+statsmodels==0.8.0 # rq.filter: >=0.7.0,<0.9