Merge branch 'patch-1' into 'master'

Update from-scratch.sh pin opencv on version 3

Just to make sure we get opencv 3 always.

See merge request !24

install/from-scratch.sh

@@ -47,7 +47,7 @@ ${CONDA} create --yes -n ${NAME} --override-channels -c conda-forge -c defaults
   nose \
   numexpr \
   numpy \
-  opencv \
+  opencv=3 \
   pillow \
   pip \
   pkg-config \