wendelin.core: Hook in-tree NumPy

Without referencing component/numpy/ numpy will be installed from just PyPI.

component/wendelin.core/buildout.cfg

@@ -3,6 +3,7 @@
 [buildout]
 extends =
   ../pygolang/buildout.cfg
+  ../numpy/buildout.cfg
   ../git/buildout.cfg
 
 parts =
@@ -27,6 +28,11 @@ setup-eggs =
     ${pygolang:egg}[pyx.build]
 environment = wendelin.core-env
 
+# dependent eggs that must come through in-tree recipes
+depends =
+    ${numpy:egg}
+
+
 [wendelin.core-env]
 # wendelin.core needs git(dev) to build
 PATH = ${git:location}/bin:%(PATH)s