* Refactor MakeBaseImage.sh to BuildImage.sh

Better name to describe what it can do: MakeBaseImage.sh to BuildImage.sh

I think it reflects better what it does: build an image from a .sh script instead of Dockerfile.

Theoretically it can be used to build any subuser image: also specialized final program images: even though it will usually be used for a simple base image: the name should better describe it. MakeBaseImage implies a kind of limitation which does in fact not exist.