Add more comprehensive layer change use cases

Signed-off-by: Michael Richters <gedankenexperimenter@gmail.com>

tests/features/layers/use-cases/sketch.json

@@ -0,0 +1,6 @@
+{
+  "cpu": {
+    "fqbn": "keyboardio:virtual:model01",
+    "port": ""
+  }
+}

tests/features/layers/use-cases/use-cases.ino

@@ -0,0 +1,80 @@
+/* -*- mode: c++ -*-
+ * Copyright (C) 2021  Keyboard.io, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <Kaleidoscope.h>
+
+// *INDENT-OFF*
+KEYMAPS(
+    [0] = KEYMAP_STACKED
+    (
+        Key_0, ___,   ___, ___, ___, ___, ___,
+        Key_0, Key_0, ___, ___, ___, ___, ___,
+        ShiftToLayer(0), ShiftToLayer(1), ShiftToLayer(2), ___, ___, ___,
+        LockLayer(0),    LockLayer(1),    LockLayer(2),    ___, ___, ___, ___,
+        MoveToLayer(0),  MoveToLayer(1),  MoveToLayer(2),  ___,
+        ___,
+
+        ___, Key_KeymapNext_Momentary, Key_KeymapPrevious_Momentary, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___, ___,
+        ShiftToLayer(0), ShiftToLayer(1), ShiftToLayer(2), ___, ___, ___,
+        ___, ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___,
+        ___
+    ),
+    [1] = KEYMAP_STACKED
+    (
+        ___,   Key_1, ___,   ___, ___, ___, ___,
+        Key_1, ___,   Key_1, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___,
+        ___,
+
+        ___, ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___,
+        ___
+    ),
+    [2] = KEYMAP_STACKED
+    (
+        ___, ___,   Key_2, ___, ___, ___, ___,
+        ___, Key_2, Key_2, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___,
+        ___,
+
+        ___, ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___, ___, ___, ___,
+        ___, ___, ___, ___,
+        ___
+    ),
+)
+// *INDENT-ON*
+
+//KALEIDOSCOPE_INIT_PLUGINS();
+
+void setup() {
+  Kaleidoscope.setup();
+}
+
+void loop() {
+  Kaleidoscope.loop();
+}