Yarko/vagrant upfix

This fixes a recent vagrant pull request to mirror development usage for native installations, that is

- git clone;
- create-dev-env.sh
- (work);
- git pull;
- (work);
- ...

scripts/vagrant-provisioning.sh:   changed to only create / initialize the workspace the first time.   Also, reported "up" IP address now reflects the VM's actual address.

README.md:  cleaned up previous notes, add info on creating clean VM; added section for django debugging toolbar and admin access