Update version for 0.7.0 release

In addition, our repository was moved to:
  git://github.com/sheepdog/sheepdog.git

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Open up 0.8 development

Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>