Add a license header
Rewrite to use libuv

Also instead of resize_term() we use resizeterm() because the former
seems to cause massive glitches.  Not flicker-free in urxvt anymore
though.
Use PROJECT_* instead of CMAKE_CURRENT_*
Fix the ANSI SGR export
Update the README
Inject some of my copy-paste library

So far only to support argument parsing, which we're going to need
soon to set up a server.