Redirect initial STDIN to each hook [closes #1]

* Use the original STDIN for the parent hook in each
  subhook.
* Just use normal UNIX pipes (`|`).
Use pre-push STDIN data in the stop-force hook.

* Use the function to prevent non fast-forward pushes in the
  Git Book:

  http://git-scm.com/book/en/Customizing-Git-An-Example-Git-Enforced-Policy
Merge pull request #2 from jhbabon/issue-1-std-redirections

Redirect initial STDIN to each hook [closes #1]