argparse.js fails 2 help related tests in test_argparse.py

TestParserDefault42 sets a parser argumentDefault
The error is that the namespace includes {help: 42, version: 42}
Correction: add defaultValue: $$.SUPPRESS when defining --help and --version
in ArgumentParser().

TestOptionalsAlternatePrefixCharsAddedHelp sets prefixChars.
If prefixChars does not include '-', setting ['-h','--help'] gives an error.
Correction: set a defaultPrefix that is either '-' or the first prefixChar,
and use this instead of '-h'
Merge pull request #36 from hpaulj/helperrors

Correct 'help' when argumentDefault and prefixChars options are used