Introducing registration, new call command

- Introduced registration of objects for the set command and functions
for the new call command
- removed addCommand from FlxG and added a reference to the console
- removed pauseSounds, resumeSounds and volume commands
- added listObjects, listFunctions, call
- substantial change of the help command, now provides info on
individual commands
- added autoPause variable to the console
- improved error prevention
- cleaned up Console.hx a bit