Fix emterpretify.py fork bomb.

Make tools/emterpretify.py import-safe by only executing itself "if __name__ == '__main__':". On Windows when using Python multiprocessing, the child processes will import the main module at launch. This means that any module that uses multiprocessing needs to be importable as a library without executing its 'task'. For reference, see http://stackoverflow.com/questions/18204782/runtimeerror-on-windows-trying-python-multiprocessing . Fixes a bug where a Windows system would hang when running emterpretify.py due to creating an avalanche of thousands of python processes.