Test for invalid octal.
Test for invalid octal.

I added a test that catches the JSError generated by invalid octal. Ricardo, can
you confirm whether this test passes or fails? You can run the tests like such:

    $ python setup.py test

[#12 state:open]

tempbottle/python-spidermonkey,hehui199135/python-spidermonkey,davisp/python-spidermonkey,tempbottle/python-spidermonkey,hehui199135/python-spidermonkey,davisp/python-spidermonkey,tempbottle/python-spidermonkey,tempbottle/python-spidermonkey,hehui199135/python-spidermonkey,hehui199135/python-spidermonkey,davisp/python-spidermonkey