split Device class to allow keeping download state

right now there's just one object for each Device type througout the whole
app. This forbids keeping actual state in the Device object during
download/cleanup.

This patch puts the list of supported Devices into a seperate class.
Actual Device objects are now created dynamically.

This is necessary for the upcoming Download changes.

src/SrmDevice.cpp

@@ -27,15 +27,17 @@
 
 #define tr(s) QObject::tr(s)
 
-static bool srm5Registered = Device::addDevice("SRM PCV", new SrmDevice( 5 ));
-static bool srm7Registered = Device::addDevice("SRM PCVI/7", new SrmDevice( 7 ));
+static bool srm5Registered =
+    Devices::addType("SRM PCV", DevicesPtr(new SrmDevices( 5 )) );
+static bool srm7Registered =
+    Devices::addType("SRM PCVI/7", DevicesPtr(new SrmDevices( 7 )));
 
 static Device::StatusCallback cb;
 
-QString
-SrmDevice::downloadInstructions() const
+DevicePtr
+SrmDevices::newDevice( CommPortPtr dev )
 {
-    return ""; // no particular instructions for SRM
+    return DevicePtr( new SrmDevice( dev, protoVersion));
 }
 
 static void progress( size_t total, size_t done, void *user_data )
@@ -64,7 +66,7 @@ get_tmpname(const QDir &tmpdir, QString &tmpname, QString &err)
 }
 
 bool
-SrmDevice::download(CommPortPtr dev, const QDir &tmpdir,
+SrmDevice::download( const QDir &tmpdir,
                     QString &tmpname, QString &filename,
                     StatusCallback statusCallback, QString &err)
 {
@@ -188,7 +190,7 @@ fail:
 }
 
 void
-SrmDevice::cleanup(CommPortPtr dev)
+SrmDevice::cleanup()
 {
     QString err;
     srmio_io_t io( NULL );