Address review comments from @loriab

Also, remove windows build, since this may be out of our scope. See:
pypa/pip#5679

recipes/hdmedians/meta.yaml

@@ -11,6 +11,7 @@ source:
 
 build:
   number: 0
+  skip: true  # [win]
   script: "{{ PYTHON }} -m pip install . --no-deps --ignore-installed --no-cache-dir -vvv "
 
 requirements:
@@ -21,9 +22,7 @@ requirements:
     - numpy
     - pip
     - python
-    - nose
   run:
-    - cython >=0.23
     - numpy
     - python
     - nose