USB Composite support

Dependents:   mbed_cdc_hid_composite

Fork of USBDevice by mbed official

Revision:
55:7c559fcb1d17
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/readme.txt	Sun May 31 15:36:50 2015 +0000
@@ -0,0 +1,22 @@
+UsbDeviceComposite
+
+!!! only tested CDC on LPC1768
+TODO: 
+    0. need to associate max packet length with endpoint
+    1. Rework HID
+    2. test Composite
+    3. rework device...
+    4. rework all HAL drivers
+
+Why not direct extend to USBDevice?
+    USBDevice has to be shared to multiple interfaces of a composite device 
+Why not multi-extend?
+    Some time need to implement 2 CDC or HIDs, can't extend twoice
+
+Composite Sample:
+    UsbComposite usb;
+    USBHID hid(&usb);
+    USBSerial ser(&usb);
+
+Single interface Sample:
+    USBHID hid;