Fix min/max private variables overflow

Author: bleubidon

src/Servo.h

@@ -115,8 +115,8 @@ class Servo
   bool attached();                   // return true if this servo is attached, otherwise false 
 private:
    uint8_t servoIndex;               // index into the channel data for this servo
-   int8_t min;                       // minimum is this value times 4 added to MIN_PULSE_WIDTH    
-   int8_t max;                       // maximum is this value times 4 added to MAX_PULSE_WIDTH   
+   int min;                          // minimum is this value times 4 added to MIN_PULSE_WIDTH    
+   int max;                          // maximum is this value times 4 added to MAX_PULSE_WIDTH   
 };
 
 #endif