Const-qualify isConnected() in base

This should be const qualified as it was before. The class state should change on 'update()' and the detector state should change on 'poll()'. This function should never change the class state.

Author: dmadison

src/SimRacing.cpp

@@ -366,7 +366,7 @@ bool Peripheral::update() {
 	return this->updateState(connected);
 }
 
-bool Peripheral::isConnected() {
+bool Peripheral::isConnected() const {
 	// if detector exists, return state
 	if (this->detector) {
 		return this->detector->isConnected();

src/SimRacing.h

@@ -281,7 +281,7 @@ namespace SimRacing {
 		*
 		* @returns 'true' if the device is connected, 'false' otherwise
 		*/
-		bool isConnected();
+		bool isConnected() const;
 
 		/** @copydoc DeviceConnection::setStablePeriod(unsigned long) */
 		void setStablePeriod(unsigned long t);