Add compilation of mpy-cross for uPython compiler.

install/97_upython.sh

+#!/bin/bash
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+. ${DIR}/common.sh
+
+# Install the scripts
+cd ${DIR} || exit 1
+
+cd .. || exit 1
+
+make -C upython-taste/mpy-cross/