Refactor UsbSerial

Remove kruft leftover from original design
Refactor flow of `begin()` method
Rename members to more accurately reflect functionality
Prune unnecessary member variables
Added destructor to clear state

source/Serial/IStream.h

@@ -1,5 +1,3 @@
-#pragma once
-
 /*
     Copyright(c) Microsoft Open Technologies, Inc. All rights reserved.
 
@@ -24,75 +22,77 @@
     THE SOFTWARE.
 */
 
+#pragma once
+
 #include <cstdint>
 
 namespace Microsoft {
 namespace Maker {
 namespace Serial {
 
 public enum class SerialConfig {
-	SERIAL_5E1,
-	SERIAL_5E2,
-	SERIAL_5N1,
-	SERIAL_5N2,
-	SERIAL_5O1,
-	SERIAL_5O2,
-	SERIAL_6E1,
-	SERIAL_6E2,
-	SERIAL_6N1,
-	SERIAL_6N2,
-	SERIAL_6O1,
-	SERIAL_6O2,
-	SERIAL_7E1,
-	SERIAL_7E2,
-	SERIAL_7N1,
-	SERIAL_7N2,
-	SERIAL_7O1,
-	SERIAL_7O2,
-	SERIAL_8E1,
-	SERIAL_8E2,
-	SERIAL_8N1,
-	SERIAL_8N2,
-	SERIAL_8O1,
-	SERIAL_8O2,
-	SERIAL_CONFIG_COUNT,
+    SERIAL_5E1,
+    SERIAL_5E2,
+    SERIAL_5N1,
+    SERIAL_5N2,
+    SERIAL_5O1,
+    SERIAL_5O2,
+    SERIAL_6E1,
+    SERIAL_6E2,
+    SERIAL_6N1,
+    SERIAL_6N2,
+    SERIAL_6O1,
+    SERIAL_6O2,
+    SERIAL_7E1,
+    SERIAL_7E2,
+    SERIAL_7N1,
+    SERIAL_7N2,
+    SERIAL_7O1,
+    SERIAL_7O2,
+    SERIAL_8E1,
+    SERIAL_8E2,
+    SERIAL_8N1,
+    SERIAL_8N2,
+    SERIAL_8O1,
+    SERIAL_8O2,
+    SERIAL_CONFIG_COUNT,
 };
 
 public delegate void RemoteWiringConnectionCallback();
-public delegate void RemoteWiringConnectionFailedCallback( Platform::String ^message );
+public delegate void RemoteWiringConnectionFailedCallback(Platform::String ^message);
 
 public interface struct IStream
 {
     virtual
     uint16_t
     available(
         void
-    ) = 0;
+        ) = 0;
 
     virtual
     void
     begin(
         uint32_t baud_,
-		SerialConfig config_
-    ) = 0;
+        SerialConfig config_
+        ) = 0;
 
     virtual
     void
     end(
         void
-    ) = 0;
+        ) = 0;
 
     virtual
     uint16_t
     read(
         void
-    ) = 0;
+        ) = 0;
 
     virtual
     uint32_t
     write(
         uint8_t c_
-    ) = 0;
+        ) = 0;
 };
 
 } // namespace Serial