Add USB code

Adds the usb code that we got in ECE 385. It will not work now, and
parts that involve the timer are disabled. It does compile though, with
a few warnings.

The goal will be to add USB MSD support, which is not actually given to
us so I will have to do myself or find some other code to base it off
of.

sw/usb/project_config.h

@@ -0,0 +1,22 @@
+/* Project name project configuration file	*/
+
+#ifndef _project_config_h_
+#define _project_config_h_
+
+#include "GenericMacros.h"
+#include "GenericTypeDefs.h"
+#include "HID.h"
+#include "MAX3421E.h"
+#include "transfer.h"
+#include "usb_ch9.h"
+#include "USB.h"
+
+/* USB constants */
+/* time in milliseconds */
+#define USB_SETTLE_TIME 					200         //USB settle after reset
+#define USB_XFER_TIMEOUT					5000        //USB transfer timeout
+
+#define USB_NAK_LIMIT 2
+#define USB_RETRY_LIMIT 3
+
+#endif // _project_config_h