Prepare for next release.

Convert Datum to throw a BinaryParsingError for more visibility.

Change the tox runner branch name to the actual branch name in this r…

…epo.

v0.9.1

Lots of stability improvements, too many to note here. This project is still in early development. Please bring any issues to the developer’s attention.

Known Issues:
* “Ambient” sounds (sound encoding 0x04) are not decoded properly and will play static.
* Asset export is SLOW due to not having decompression logic written in C.
* The following known titles are NOT supported in this release:
    * Stuart - 4.0r8 - 1.0US - English - Windows
        * A popular ISO floating around seems to have a corrupted 2048-byte block from a CD read error, and asset extraction will choke on that.
    * Pocahontas - 3.1.1 - 1.0DE - German - Windows
    * George Shrinks - NA - 1.0 - English - Windows

Rename internal variables to prevent JSON export.

I just use a single underscore to indicate loosely "protected" variables (those that shouldn't be included in a JSON export). Maybe this isn't the best approach because it mixes the concepts of data visibility in classes with data included in the JSON export, but it was definitely the easiest at the time since the jsons library has a way to ignore private/protected class members but not another easy way to ignore arbitrary class members.