While at it, removing unused interface.

I understand the intent when this was first created but nobody is using it and it no longer fits the context. If and when a need to abstract the serial link comes back, we can revisit this.

src/comm/SerialLinkInterface.h

-/*=====================================================================
-
-QGroundControl Open Source Ground Control Station
-
-(c) 2009 - 2011 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
-
-This file is part of the QGROUNDCONTROL project
-
-    QGROUNDCONTROL is free software: you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    QGROUNDCONTROL is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with QGROUNDCONTROL. If not, see <http://www.gnu.org/licenses/>.
-
-======================================================================*/
-
-/**
- * @file
- *   @brief Brief Description
- *
- *   @author Lorenz Meier <mavteam@student.ethz.ch>
- *
- */
-
-#ifndef SERIALLINKINTERFACE_H_
-#define SERIALLINKINTERFACE_H_
-
-#include <QObject>
-#include <QString>
-#include <QVector>
-#include <LinkInterface.h>
-
-/*
-class SerialLinkInterface : public LinkInterface
-{
-    Q_OBJECT
-
-public:
-    virtual QString getPortName() const = 0;
-    virtual int getBaudRate() const = 0;
-    virtual int getDataBits() const = 0;
-    virtual int getStopBits() const = 0;
-    virtual void requestReset() = 0;
-    virtual int getBaudRateType() const = 0;
-    virtual int getFlowType() const = 0;
-    virtual int getParityType() const = 0;
-    virtual int getDataBitsType() const = 0;
-    virtual int getStopBitsType() const = 0;
-
-public slots:
-    virtual bool setPortName(QString portName) = 0;
-    virtual bool setBaudRate(int rate) = 0;
-    virtual bool setBaudRateType(int rateIndex) = 0;
-    virtual bool setFlowType(int flow) = 0;
-    virtual bool setParityType(int parity) = 0;
-    virtual bool setDataBitsType(int dataBits) = 0;
-    virtual bool setStopBitsType(int stopBits) = 0;
-    virtual void loadSettings() = 0;
-    virtual void writeSettings() = 0;
-
-};
-*/
-
-/* Declare C++ interface as Qt interface */
-//Q_DECLARE_INTERFACE(SerialLinkInterface, "org.openground.comm.links.SerialLinkInterface/1.0")
-
-#endif // SERIALLINKINTERFACE_H_