Explicitly add scripts package.

Author: tannewt

setup.py

@@ -9,7 +9,8 @@
       author='Scott Shawcroft',
       author_email='[email protected]',
       url='https://www.adafruit.com/',
-      packages=['circuitpython_build_tools'],
+      packages=['circuitpython_build_tools',
+                'circuitpython_build_tools.scripts'],
       package_data={'circuitpython_build_tools': ['data/mpy-cross-*']},
       zip_safe=False,
       python_requires='>=3.4',