Remove all manual tracking of which tokens would have been accepted by
the parser in favor of having the parser add tokens that it checks for
to a set of expected tokens, clearing them when it accepts a token, and
using the current contents of the set in error messages.
This is a massive improvement, and will make the parser easier to
modify going forward.
And, this actually solves my sole issue with hand-written parsers.
Thanks to matklad on reddit for suggesting this!
The `--choose` subcommand runs a chooser to select a recipe to run. The
chooser should read lines containing recipe names from standard input,
and write one of those names to standard output.
The chooser defaults to `fzf`, a popular fuzzy finder, but can be
overridden by setting $JUST_CHOOSER or passing `--chooser <CHOOSER>`.
Combine all integration test binaries into a single binary with the root
in `tests/lib.rs`. This also turns of automatic test discovery, so
when adding another set of integration tests, a mod statement will need
to be added to `tests/lib.rs`.
