Merge pull request #19 from NickBoyadjian/patch-1

Add documentation for doom emacs in the read me

Overhaul inf-elixir-send-* buffer lookup

This is a relatively complex flow that I've wanted to revisit for some
time. I will be uploading a diagram to the wiki that encapsulates most
of the flow.

Also introduces a new `inf-elixir-set-repl` command which allows the
user to manually set what REPL they want the current buffer to send
to. This choice is remembered until the buffer is killed or the
command is run again.

Write a slightly better error message

Bail out of `inf-elixir-project' if project root not found

Add "sent" commands to comint history

Update to v2.0.0

Update to v1.0.1

Add note to README about keybindings