Allow more audio to be pulled out, plus more

Sorry for the late reply. After I saw Issue #3 and used it, I found that the was more than one error stopping every last piece (or so I guess) of audio from being pulled out. This PR fixes that, so all Exceptions are caught. In addition, this PR also contains....

* Fixes all PEP 8 errors,
* Removes broken Py3K code (I could not make it compatible at all. I'm not knowledgeable enough in Python to do that yet),
* Opens a Tkinter File Dialog if the command-line argument is not invoked (from another version of LIME we talked about in Issue #2)

I am very interesting in this project, as well as a whole international community, because LEGO Island is one of the most beloved LEGO video games, and as a modding community, LIME is of special interest because even the most skilled modders have been unable to open the SI archives to get the files out; LIME is the first successful program to ever do that.

The script has been tested successfully tested on Python 2.7.5 on Windows. :smile:

Oh, and a tip for the `rewrite` branch: when trying to extract the files, don't attempt to convert them or anything. As modders, our job is to get the files out in their original form, document the format and recreate it, and have the game load the new files. :wink:

Oh, and this PR would close #2 if you choose to merge it. :wink: