Add smt keymap for Clueboard (HHKB-style layout) (#1286)

* Add keymap for smt Clueboard (HHKB layout)

* Add readme for smt Clueboard (HHKB) keymap

* Flesh out the keymap a bit more to support Colemak & Dvorak

* Update README with layout image

keyboards/clueboard/keymaps/smt/readme.md

@@ -0,0 +1,30 @@
+```
+ ___     _____ _            _                         _     __    __ _   __
+|__ \   / ____| |          | |                       | |   / /   / /(_) / /
+ ||) | | |    | |_   _  ___| |__   ___   __ _ _ __ __| |  / /_  / /_   / /
+ |/ /  | |    | | | | |/ _ \ '_ \ / _ \ / _` | '__/ _` | | '_ \| '_ \ / /
+ |_|   | |____| | |_| |  __/ |_) | (_) | (_| | | | (_| | | (_) | (_) / / _
+ (_)    \_____|_|\__,_|\___|_.__/ \___/ \__,_|_|  \__,_|  \___/ \___/_/ (_)
+```
+
+# smt Clueboard Layout (HHKB variant)
+
+![Clueboard Layout Image](layout.png)
+
+This is smt's HHKB variant layout, based on the default layout that comes
+flashed on every Clueboard. The primary differences from the default are:
+
+- The Backspace key is moved down into the traditional `\` position
+- `\` and `` ` `` are assigned to the "split-backspace" positions
+- The right Shift is split to allow for a Fn key to its right
+- The modifiers on the right side now mirror the left side (`Alt`/`Super`/`Ctrl`)
+
+For the most part, it's a straightforward and easy to follow layout. There
+are a few special keys:
+
+- The Esc key sends `Esc` when tapped, `` ` `` when `Alt`/`Super`/`Ctrl`/`Fn` is held, or `~` when `Shift` is held
+- The Tab key sends `Tab` when tapped, or `Super+Ctrl+Alt+Shift` (a.k.a. [Hyper]) when held
+- The key traditionally in the Caps-Lock position has been re-mapped to send `Esc` when tapped, or `Ctrl` when held
+- The left Shift key sends `Enter` when tapped, or `Shift` when held
+
+[Hyper]: http://brettterpstra.com/2012/12/08/a-useful-caps-lock-key/