tests: Add support for "Chef tests", which are direct CLI tests. Since Chef tests are written as YAML tests and also involve creating a mock file-system, this change includes a refactor of the bake tests to put some functionality in a common base class.

#!/bin/sh

CHEF_DIR=`dirname $0`
if `hash readlink 2>&-`; then
    LINKED_EXE=`readlink $0`
    if [ -n "$LINKED_EXE" ]; then
        CHEF_DIR=`dirname $LINKED_EXE`
    fi
fi
python $CHEF_DIR/../chef.py $@