parser: Add `key_code` and `special_key` parsers

Still need to test them though. They'll be used in conjunction with
another new parser, `action_map`, which will parser map-type action
strings.

`key_code` parses `autopilot::key::KeyCode`s, basically all special keys
and modifiers. `special_key` parses key codes inside `<` `>` braces.

Change the test to use `easy_parse` to give a clear error message.

Add `recursion_limit` to the crate on the advice of the compiler in
order for the `choice!` macro in `key_code()` to work properly.
Otherwise it spits out a giant error message complaining about
`rustc --explain E0277`. If I remove a handful of elements from the
`choice!`, it compiles, so it seems there's an upper bound restricted by
the recursion limit.

Modifier keys are included in a commented section as these are part of
the 'autopilot' `KeyCode` enum, but they'll be handled in a separate
parser.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
index b51b165..c6f66d1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,5 @@
+#![recursion_limit="128"]
+
 extern crate autopilot;
 // extern crate cocoa;