First USB.H with usb 2.0 spec defs

Usb 2.0 specification definitions:
Status, Requests and Descriptors
First USB_CDC.H with usb 2.0, cdc/acm spec defs

CDC and ACM specifications definitions:
Requests, Notifications, Functional Descriptors,
Communications and Data interfaces
GPLv3 added to LICENSE in DOC directory
Setup packet definition added to usb.h
doc/LICENSE is now a soft link to doc/gpl.txt
First USB_PIC.H with pic datasheet defs

PIC18F45505 Datasheet:
Buffer descriptor tables
Interface usb function declarations added to USB.H

Main usb functions declared:
- usb_handler()
- usb_init()
- usb_is_configured()
Interface usb/cdc function declarations added

Interface functions for usb/cdc control:
- usb_cdc_putc()
- usb_cdc_getc()
- usb_cdc_puts()
- usb_cdc_gets()