Fix up visibility, move more complex car movements into subclass.

Sources/Swift2dCar/Servo.swift

@@ -10,12 +10,12 @@
 import Foundation
 import SwiftyGPIO
 
-enum ServoError: Error{
+public enum ServoError: Error{
     case invalidMinPulseWidth
     case invalidMaxPulseWidth
 }
 
-protocol Servo {
+public protocol Servo {
     var value: Float {get set}
     
     var minPulseWidth: Float {get}
@@ -40,25 +40,25 @@ public class PWMHardwareServo : Servo{
     private var device: PWMOutput
     private var currentPulseWIdth: Float
     
-    var minPulseWidth: Float {
+    public var minPulseWidth: Float {
         get{
             return minDc * frameWidth
         }
     }
     
-    var maxPulseWidth: Float{
+    public var maxPulseWidth: Float{
         get{
             return (dcRange * frameWidth) + minPulseWidth
         }
     }
     
-    var pulseWidth: Float{
+    public var pulseWidth: Float{
         get{
             return internalValue * frameWidth
         }
     }
     
-    var value: Float{
+    public var value: Float{
         get{
             internalValue
         }
@@ -71,7 +71,7 @@ public class PWMHardwareServo : Servo{
     }
 
     
-    init?(forPin pin: PWMOutput, startingAt initialValue: Float = 0, withMinPulseWidth minPulseWidth: Float = 1000000,
+    public init?(forPin pin: PWMOutput, startingAt initialValue: Float = 0, withMinPulseWidth minPulseWidth: Float = 1000000,
           withMaxPulseWidth maxPulseWidth: Float = 2000000, withFrameWidth frameWidth: Float = 20000000) throws {
         if(minPulseWidth >= maxPulseWidth){
             throw ServoError.invalidMinPulseWidth
@@ -95,19 +95,19 @@ public class PWMHardwareServo : Servo{
         self.device.startPWM(period: Int(self.frameWidth), duty: self.minDc + self.dcRange * ((internalValue - self.minValue) / self.valueRange) * 100)
     }
     
-    func min(){
+    public func min(){
         self.value = -1
     }
     
-    func mid(){
+    public func mid(){
         self.value = 0
     }
     
-    func max() {
+    public func max() {
         self.value = 1
     }
     
-    func detach(){
+    public func detach(){
         self.device.stopPWM()
     }
 }