Fixed various bugs and improved documentation.

- Fixed checkContent() example in README to account for potential user edits when checking CAPTCHA.
- Revamped README formatting.
- Added license to README.
- Fixed class member method visibility: properties that can be set by the application should also be readable by the application.
- Use consistent order for Mollom API property names and methods everywhere to avoid bugs/oversights.
- Removed lastMatch and matchCount from Whitelist entry entity.
- Removed stale docs on acceptAllPostsOnError.
- Added missing blacklist entry contexts.
- Fixed Content unsure and strictness parameters should only be sent when checking spam.
- Fixed Content stored parameter should only be sent upon storage changes.
- Fixed Content reason is not merged into Content object.
- Fixed Captcha ssl and rateLimit parameters should only be sent when non-zero.
- Fixed Captcha contentId parameter should only be sent when non-empty.
- Fixed Feedback may only be sent with a content and/or CAPTCHA ID, and a given reason.
- Fixed stored Blacklist/Whitelist entry values are not necessarily identical to the input value.