This commit moves all the input-related files from `core/`
to `core/input/`, and renames a couple as relevant
(input.js --> input/devices.js, keyboard.js --> input/util.js).
The event-related wrapper functions in Util existed mainly for
backwards-compat. However, all currently supported browsers
support the standard functions, so these wrappers are no longer needed.
This commit restructures noVNC, splitting it into the core directory
and the app directory, with the former containing core noVNC parts,
and the latter containing parts specific to the application.
samhed
Solly Ross