wev: a Wayland analogue to X11's xev

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!