Fix prefix and suffix, commands execution otimization.

[rube200]

About permissions; It should do some checks before starting call functions that will not be used in some cases.
Example:

IRocketCommand command = R.Commands.GetCommand(requestedCommand);
double cooldown = R.Commands.GetCooldown(player, command);

If the command does not exist, rocketmod should not call GetCooldown.

About prefixes and suffixes: i changed the event from Provider.onCheckValid to Provider.onCheckValidWithExplanation and some otimizations.

btw rocketmod currently listen Provider.onCheckValidWithExplanation so Provider.onCheckValid is never called

[ennerperez]

Looks great

[SDGNelson]

This sounds like a good change, especially fixing the usage of onCheckValid. Will examine further soon.

[CLAassistant]

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