Feature If you can't pickpocket, steal() should do nothing instead of attacking

[slyz]

From RuntomeLibrary.java:

public static Value steal()
{
	if ( !FightRequest.canStillSteal() )
	{
		return RuntimeLibrary.attack();
	}

	return RuntimeLibrary.visit_url( "fight.php?action=steal" );
}

I think returning without doing anything when FightRequest.canStillSteal() is false is a better behavior.