It's not really fair to refer to the main index function as "legacy" if it's actively being used. All controller-specific 'get' filtering functions are now appended with the name of the controller rather than having it in the middle.
Move shared button identifiers from enum to an inline function, so formerly shared identifiers can be separately filtered and processed on a class-by-class basis.
Fixes#611.
The following collisions resolved:
hid.h -> usbhid.h
hid.cpp -> usbhid.cpp
HID -> USBHID
HID_BOOT_PROTOCOL -> USB_HID_BOOT_PROTOCOL
HID_PROTOCOL_NONE -> USB_HID_PROTOCOL_NONE
HID_PROTOCOL_KEYBOARD -> USB_HID_PROTOCOL_KEYBOARD
HID_PROTOCOL_MOUSE -> USB_HID_PROTOCOL_MOUSE
As a result, it's possible to use the library together with Arduino's bundled HID / Mouse / Keyboard libraries (Leonardo, Micro, or Due).
https://www.arduino.cc/en/Reference/MouseKeyboard
