Fixed and reworked most of the API.
Improved perfomance by inling getter and setter.
Fixed license.
Renamed IEngineSingleton to GhrumAPI.
Reworde CommandReader
Merge branch 'master' of https://github.com/Wolftein/GhrumAPI

Conflicts:
	include/Command/CommandException.hpp
	include/Command/CommandReaderException.hpp
	include/Command/ICommand.hpp
	include/Command/ICommandSender.hpp
	include/Common.hpp
	include/Core/IEngine.hpp
	include/Core/IEngineServer.hpp
	include/Core/IEngineSingleton.hpp
	include/Event/Event.hpp
	include/Event/EventListener.hpp
	include/Event/EventPriority.hpp
	include/Event/IEventManager.hpp
	include/Network/IMessage.hpp
	include/Network/IMessageCodec.hpp
	include/Network/IMessageHandler.hpp
	include/Network/IMessageInputStream.hpp
	include/Network/IMessageOutputStream.hpp
	include/Network/ProtocolMode.hpp
	include/Permission/IPermissible.hpp
	include/Permission/IPermissibleGroup.hpp
	include/Permission/IPermissionManager.hpp
	include/Plugin/IPlugin.hpp
	include/Plugin/IPluginManager.hpp
	include/Plugin/Platform.hpp
	include/Plugin/PluginDescriptor.hpp
	include/Plugin/PluginException.hpp
	include/Plugin/PluginOrder.hpp
	include/Plugin/PluginType.hpp
	include/Scheduler/IScheduler.hpp
	include/Scheduler/ITask.hpp
	include/Scheduler/ITaskManager.hpp
	include/Scheduler/TaskPriority.hpp
	include/Utilities/Delegate.hpp
	include/Utilities/Expression.hpp