Better logging documentation and more

- Improved documentation for the new logging functions in FlxG a ton.
Especially important since they could be confusing due to showing up as
fields in auto-comletion (FD at least)
- Added formatHash() to FlxU
- Improved help command once more
- fixed bug where FlxG.advancedLog()'s Data param had to be an Array or
would cause an error otherwise