0.1.4

Added new callbacks, use those before USH.init:

  USH.setOnConfigDescCB( Default_USB_ConfigDescCB ); // found a config descriptor
  USH.setOnIfaceDescCb( Default_USB_IfaceDescCb ); // found an interface descriptor
  USH.setOnHIDDevDescCb( Default_USB_HIDDevDescCb ); // found a HID Device descriptor
  USH.setOnEPDescCb( Default_USB_EPDescCb ); // found an endpoint descriptor

Fix #39

Although usbSetFlag() was implemented, numlock/scrolllock/capslock led controls were missing from the example.
This has been corrected by adding a call to usbSetFlag(int _usb_num, uint8_t flags) in the KeyboardReportParser base class.