Fixed compile error on StandardFirmata example.

Revert "Servo library refactoring. See #1617"

This reverts commit e8834d32f3.

See #1617

libraries/Servo/arch/avr/Servo.cpp

@@ -20,8 +20,7 @@
 #include <avr/interrupt.h>
 #include <Arduino.h> 
 
-#include <Servo.h>
-#include "ServoTimers.h"
+#include "Servo.h"
 
 #define usToTicks(_us)    (( clockCyclesPerMicrosecond()* _us) / 8)     // converts microseconds to tick (assumes prescale of 8)  // 12 Aug 2009
 #define ticksToUs(_ticks) (( (unsigned)_ticks * 8)/ clockCyclesPerMicrosecond() ) // converts from ticks back to microseconds

libraries/Servo/arch/sam/Servo.cpp

@@ -19,7 +19,6 @@
 
 #include <Arduino.h> 
 #include <Servo.h>
-#include "ServoTimers.h"
 
 #define usToTicks(_us)    (( clockCyclesPerMicrosecond() * _us) / 32)     // converts microseconds to tick
 #define ticksToUs(_ticks) (( (unsigned)_ticks * 32)/ clockCyclesPerMicrosecond() ) // converts from ticks back to microseconds

libraries/Servo/src/Servo.h

@@ -58,6 +58,9 @@
  * _Nbr_16timers indicates how many 16 bit timers are available.
  */
 
+// Architecture specific include
+#include <ServoTimers.h>
+
 #define Servo_VERSION           2     // software version of this library
 
 #define MIN_PULSE_WIDTH       544     // the shortest pulse sent to a servo