Update the ergodox-ez/algernon keymap (#409)

Update the ergodox-ez/algernon keymap (#409)

Compared to the previous version, the following noteworthy changes have
been made to the keymap:

* The keyboard starts in NKRO mode, bootmagic and other things are
  disabled.
* A STENO layer was added, to be used with Plover.
* An experimental layout was added, something halfway between Dvorak and
  Capewell-Dvorak. A work in progress.
* `LEAD y` types \o/.
* Some keys on the BASE layer have been moved around:
  - `?` moved to the left pinky, left of `Q`.
  - `=` shifted one row down, but `F11` stayed where it was.
  - `-` on the left half was replaced by `Tab`.
  - `Tab`'s original position is taken by a `Media Next`/`Media Prev`
     key.
  - `:` now inputs `;` when shifted.
* `ESC` cancels the **HUN** layer too, not just modifiers.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>