Fixed integer primitive to ensure that embedded values are ints and not floats

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Change som.sh to prefer pypy as default Python

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Added clean target and execute test harness as part of test target

Signed-off-by: Stefan Marr <git@stefan-marr.de>