PluggableUSB: modules modify bcdDevice value

This should solve driver mismatch in Windows when a different USBDevice functionality is added/removed.
Based on this suggestion: arduino-libraries/Keyboard#41 (comment)

Author: sabas1080

cores/arduino/USB/PluggableUSBDevice.cpp

@@ -95,6 +95,7 @@ bool arduino::PluggableUSBDevice::plug(internal::PluggableUSBModule*node)
 
     node->pluggedInterface = lastIf;
     lastIf += node->numInterfaces;
+    product_release += node->getProductVersion();
     return true;
 }
 

cores/arduino/USB/PluggableUSBDevice.h

@@ -58,6 +58,7 @@ class PluggableUSBModule {
     virtual void callback_set_interface(uint16_t interface, uint8_t alternate);
     virtual void init(EndpointResolver& resolver);
     virtual const uint8_t *string_iinterface_desc();
+    virtual uint8_t getProductVersion();
 
     uint8_t pluggedInterface;
 

cores/arduino/USB/USBCDC.cpp

@@ -489,6 +489,11 @@ const uint8_t *USBCDC::string_iinterface_desc()
     return (const uint8_t *)extraDescriptor;
 }
 
+uint8_t USBCDC::getProductVersion()
+{
+    return 1;
+}
+
 const uint8_t *USBCDC::string_iproduct_desc()
 {
     static const uint8_t stringIproductDescriptor[] = {

cores/arduino/USB/USBCDC.h

@@ -144,6 +144,13 @@ class USBCDC: public internal::PluggableUSBModule{
     */
     virtual const uint8_t *string_iproduct_desc();
 
+    /*
+    * Get string product version
+    *
+    * Every module must declare a different number
+    */
+    virtual uint8_t getProductVersion();
+
     /*
     * Get string interface descriptor
     *