Changed
-------

*   Rename the JSON parser class to ``JSONParser``.
*   Rename the base feedparser exception to ``FeedparserError``.
*   Use full sentences in comments.
*   Fix some PEP8 issues throughout the code.
*   Remove unnecessary underscore prefixes from classes and functions.
*   Drop some Python 2 compatibility code.
    For example, classes no longer explicitly inherit from ``object``.
