Make more shebangs compatible (#30)

Several of the tests continue to refer to /usr/bin/python. I don't
know of a way to fix these, as they call python -S and IIRC shebangs
can only include one parameter…

build/doc.sh

@@ -1,4 +1,4 @@
#!/bin/bash
#!/usr/bin/env bash
#
# Usage:
#   ./run.sh <function name>

build/quick_ref.py

@@ -1,4 +1,4 @@
#!/usr/bin/python
#!/usr/bin/env python
"""
quick_ref.py
"""