Adding colemak keyboard layout option to keyboard-layout

- Base Remapping Keys

`#{n, e, i, o}` <=> `#{h, j, k, l}`

- setting `avy` keys to the `colemak` home row keys

`#{a, r, s, t, n, e, i, o}`

- adjusting leader key to `tn`

- overriding evil org mode bindings especially for 'o'

- one character key guess rebindings can give back empty string
when looking for the prefix and it isn't empty, then guess the rebindings --
this fix lets the check not pass and return `'(nil nil)`, allowing the
`(remove-if #'null)` to actually work.

- correcting magit staging when using visual line

layers/+intl/keyboard-layout/README.org

@@ -12,6 +12,8 @@
  - [[#keyboard-layouts][Keyboard layouts]]
    - [[#bepo][bepo]]
    - [[#dvorak][dvorak]]
+   - [[#colemak][colemak]]
+     - [[#remapped-keys][Remapped Keys]]
  - [[#package-configurations][Package Configurations]]
  - [[#keybindings][Keybindings]]
  - [[#sources][Sources]]
@@ -148,6 +150,16 @@ will remap keybindings for the =dvorak-programmer= variant.
 
 [[file:img/dvorak-keymap.png]]
 
+** colemak
+   =colemak= is a keyboard layout designed for touch typing in English.
+
+   [[file:img/colemak-layout.png]]
+
+*** Remapped Keys
+
+    - ~avy~ and ~ace-window~ keys are remapped to the ~colemak~ home row
+    - ~evil-leader~ is also remapped to ~tn~
+
 * Package Configurations
 The available configurations are:
 

layers/+intl/keyboard-layout/config.el

@@ -14,7 +14,7 @@
 ;;------------------------------------------------------------------------------
 
 (defvar kl-layout 'dvorak
-  "The keyboard-layout to use. Possible values are `dvorak' and `bepo'.")
+  "The keyboard-layout to use. Possible values are `colemak', `dvorak' and `bepo'.")
 
 (defvar kl-enabled-configurations nil
   "If non nil, `keyboard-layout' will enable configurations only
@@ -41,6 +41,15 @@ any case.")
              ("j" . "t")
              ("k" . "s")
              ("l" . "c")))
+    (colemak . (("n" . "h")
+                ("e" . "j")
+                ("i" . "k")
+                ("o" . "l")
+                ;;
+                ("h" . "n")
+                ("j" . "e")
+                ("k" . "i")
+                ("l" . "o")))
     (dvorak . (("h" . "h")
                ("t" . "j")
                ("n" . "k")

layers/+intl/keyboard-layout/funcs.el

@@ -27,7 +27,7 @@
                (mapcar
                 (lambda (modifier)
                   (cons (concat modifier key1) (concat modifier key2)))
-                '("" "C-" "M-" "C-S-")))))
+                '("C-" "M-" "C-S-")))))
           basemap))
 
 (defun kl//define-key (maps key def bindings)
@@ -81,7 +81,8 @@ key."
     (let* ((key2 (cdr (assoc key1 rebinding-map)))
            (bind1 (assoc key1 rebinding-map))
            (bind2 (assoc key2 rebinding-map)))
-      (when prefix
+      (when (and prefix
+                 (not (string-empty-p prefix)))
         (defun kl//guess-prefixit (bind)
           `(,(concat prefix (car bind)) . ,(concat prefix (cdr bind))))
         (setq bind1 (kl//guess-prefixit bind1))

layers/+intl/keyboard-layout/packages.el

@@ -42,6 +42,8 @@
     (spacemacs|use-package-add-hook ace-window :post-init BODY)
     :bepo
     (setq aw-keys '(?a ?u ?i ?e ?t ?s ?r ?n))
+    :colemak
+    (setq aw-keys '(?a ?r ?s ?t ?n ?e ?i ?o))
     :dvorak
     (setq aw-keys '(?a ?o ?e ?u ?h ?t ?n ?s))))
 
@@ -53,6 +55,8 @@
     (spacemacs|use-package-add-hook avy :post-init BODY)
     :bepo
     (setq-default avy-keys '(?a ?u ?i ?e ?t ?s ?r ?n))
+    :colemak
+    (setq-default avy-keys '(?a ?r ?s ?t ?n ?e ?i ?o))
     :dvorak
     (setq-default avy-keys '(?a ?o ?e ?u ?h ?t ?n ?s))))
 
@@ -171,7 +175,9 @@
     :loader
     (spacemacs|use-package-add-hook evil-escape :post-init BODY)
     :bepo
-    (setq-default evil-escape-key-sequence "gq")))
+    (setq-default evil-escape-key-sequence "gq")
+    :colemak
+    (setq-default evil-escape-key-sequence "tn")))
 
 (defun keyboard-layout/pre-init-evil-evilified-state ()
   (kl|config evil-evilified-state
@@ -308,11 +314,14 @@
     (spacemacs|use-package-add-hook magit :post-config BODY)
     :common
     (progn
-      (kl/evil-correct-keys evil-magit-state magit-mode-map
-        "j"
-        "k"
-        "C-j"
-        "C-k")
+      (dolist (state (if evil-magit-use-y-for-yank
+                         (list evil-magit-state 'visual)
+                       (list evil-magit-state)))
+        (kl/evil-correct-keys state magit-mode-map
+          "j"
+          "k"
+          "C-j"
+          "C-k"))
       (kl/evil-correct-keys 'normal evil-magit-toggle-text-minor-mode-map
         "C-j")
       (dolist (map (list magit-branch-section-map
@@ -436,7 +445,18 @@
         "gk" nil
         ;; additional
         (kbd "«") 'org-metaleft
-        (kbd "»") 'org-metaright))))
+        (kbd "»") 'org-metaright))
+    :colemak
+    (progn
+      (spacemacs|use-package-add-hook evil-org
+        :post-config
+        (progn
+          (evil-define-key 'normal evil-org-mode-map
+            "O" 'org-forward-heading-same-level
+            "o" 'evil-forward-char
+            "E" 'org-forward-element
+            "I" 'org-backward-element
+            "N" 'org-backward-heading-same-level))))))
 
 (defun keyboard-layout/pre-init-org-agenda ()
   (kl|config org-agenda