Place bundled library under src folder

All recent versions of the Arduino IDE restrict recursive compilation to the src subfolder of the sketch folder. The previous use of the lib folder to store the bundled library caused compilation to fail:

C:\Users\per\AppData\Local\Temp\ccJTFh0h.ltrans0.ltrans.o: In function `setup':

C:\Users\per\Desktop\G27_Pedals_and_Shifter/G27_Pedals_and_Shifter.ino:359: undefined reference to `G27'

C:\Users\per\Desktop\G27_Pedals_and_Shifter/G27_Pedals_and_Shifter.ino:359: undefined reference to `G27'

C:\Users\per\Desktop\G27_Pedals_and_Shifter/G27_Pedals_and_Shifter.ino:359: undefined reference to `G27_::begin(bool)'

etc.

Reference:
arduino/arduino-builder#148

Author: per1234

G27_Pedals_and_Shifter.ino

@@ -5,7 +5,7 @@
 // http://www.isrtv.com/forums/topic/13189-diy-g25-shifter-interface-with-h-pattern-sequential-and-handbrake-modes/
 
 #include <HID.h>
-#include "./lib/G27PedalsShifter.h"
+#include "./src/G27PedalsShifter.h"
 
 // comment either out to disable
 #define USE_PEDALS