Keymap: Merlin Learns to QMK (#3820)

* Fix up my keymaps to use more QMK features

* update 60_ansi readme

* add the start of my userspace

* begin to use my new userspace

* use more of my userspace

* spread userspace love to my clueboard

* spread userspace love to 75 layout

* add a fairly vanilla readme

* put the FNX into a userspace incase I ever want to use it for something else

* respond to drashna's code review comments

users/mechmerlin/mechmerlin.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include "quantum.h"
+
+enum userspace_layers {
+  _BL = 0, // Base Layer
+  _FL,     // Function Layer
+  _AL      // Arrow Layer
+};
+
+// Enum of custom keycodes defined in process_record_user
+enum keycodes {
+    KC_FNX, // Hold for FN layer, tap to toggle ARROWS layer. 
+};
+
+// Custom #defined keycodes
+#define KC_CTCP MT(KC_LCTL, KC_CAPS)