wev: a Wayland analogue to X11's xev

[Drew DeVault]

A lazy Sunday project. Opens an XDG toplevel and prints interesting
events. Does other useful things like maintaining an XKB state and
printing key events in the form of keysyms and UTF-8 strings, dumping
keymaps to a file, and filtering out events you aren't interested in.
For sway at least, I imagine that this will solve questions like "what
key name do I put in my config file to bind to <obscure key>?"

I hope someone finds it useful!