SocketCan: Rename to SerialBusConnection

QtCanBus is not limited to SocketCAN, it also supports various
Windows CAN adapters directly.

Also, add the term Connection to describe the inheritance
hierarchy better.

connections/canconfactory.cpp

@@ -1,6 +1,6 @@
 #include <QString>
 #include "canconfactory.h"
-#include "socketcan.h"
+#include "serialbusconnection.h"
 #include "gvretserial.h"
 
 using namespace CANCon;
@@ -9,7 +9,7 @@ CANConnection* CanConFactory::create(type pType, QString pPortName)
 {
     switch(pType) {
         case SOCKETCAN:
-            return new SocketCan(pPortName);
+            return new SerialBusConnection(pPortName);
         case GVRET_SERIAL:
             return new GVRetSerial(pPortName);
         default: {}