Add KEYMAP macros for more readable keymap definitions

For those who'd like to work with C arrays, instead of generating
layouts from some other source, the `KEYMAP` macro makes it easier to
define a layer. The parameters in the macro arguments are arranged in
such a way that they can be formatted in a way that matches each hand
more closely. Similarly, a `KEYMAP_STACKED` is introduced, where the
hands are under each other, not side-by-side.

This is just aesthetics, for the C-savvier users.

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

src/Model01.h

@@ -176,3 +176,37 @@ class Model01 {
 #define LED_APOSTROPHE 62
 #define LED_MINUS 63
 
+#define KEYMAP_STACKED(                                                 \
+               r0c0, r0c1, r0c2, r0c3, r0c4, r0c5, r0c6,                \
+               r1c0, r1c1, r1c2, r1c3, r1c4, r1c5, r1c6,                \
+               r2c0, r2c1, r2c2, r2c3, r2c4, r2c5,                      \
+               r3c0, r3c1, r3c2, r3c3, r3c4, r3c5, r2c6,                \
+               r0c7, r1c7, r2c7, r3c7,                                  \
+               r3c6,                                                    \
+                                                                        \
+               r0c9,  r0c10, r0c11, r0c12, r0c13, r0c14, r0c15,         \
+               r1c9,  r1c10, r1c11, r1c12, r1c13, r1c14, r1c15,         \
+                      r2c10, r2c11, r2c12, r2c13, r2c14, r2c15,         \
+               r2c9,  r3c10, r3c11, r3c12, r3c13, r3c14, r3c15,         \
+               r3c8,  r2c8,  r1c8, r0c8,                                \
+               r3c9)                                                    \
+  {                                                                     \
+    {r0c0, r0c1, r0c2, r0c3, r0c4, r0c5, r0c6, r0c7, r0c8, r0c9, r0c10, r0c11, r0c12, r0c13, r0c14, r0c15}, \
+    {r1c0, r1c1, r1c2, r1c3, r1c4, r1c5, r1c6, r1c7, r1c8, r1c9, r1c10, r1c11, r1c12, r1c13, r1c14, r1c15}, \
+    {r2c0, r2c1, r2c2, r2c3, r2c4, r2c5, r2c6, r2c7, r2c8, r2c9, r2c10, r2c11, r2c12, r2c13, r2c14, r2c15}, \
+    {r3c0, r3c1, r3c2, r3c3, r3c4, r3c5, r3c6, r3c7, r3c8, r3c9, r3c10, r3c11, r3c12, r3c13, r3c14, r3c15}, \
+  }
+
+#define KEYMAP(                                                                                     \
+  r0c0, r0c1, r0c2, r0c3, r0c4, r0c5, r0c6,        r0c9,  r0c10, r0c11, r0c12, r0c13, r0c14, r0c15, \
+  r1c0, r1c1, r1c2, r1c3, r1c4, r1c5, r1c6,        r1c9,  r1c10, r1c11, r1c12, r1c13, r1c14, r1c15, \
+  r2c0, r2c1, r2c2, r2c3, r2c4, r2c5,                     r2c10, r2c11, r2c12, r2c13, r2c14, r2c15, \
+  r3c0, r3c1, r3c2, r3c3, r3c4, r3c5, r2c6,        r2c9,  r3c10, r3c11, r3c12, r3c13, r3c14, r3c15, \
+              r0c7, r1c7, r2c7, r3c7,                             r3c8,  r2c8,  r1c8, r0c8,         \
+                          r3c6,                                          r3c9)                      \
+  {                                                                                                 \
+    {r0c0, r0c1, r0c2, r0c3, r0c4, r0c5, r0c6, r0c7, r0c8, r0c9, r0c10, r0c11, r0c12, r0c13, r0c14, r0c15}, \
+    {r1c0, r1c1, r1c2, r1c3, r1c4, r1c5, r1c6, r1c7, r1c8, r1c9, r1c10, r1c11, r1c12, r1c13, r1c14, r1c15}, \
+    {r2c0, r2c1, r2c2, r2c3, r2c4, r2c5, r2c6, r2c7, r2c8, r2c9, r2c10, r2c11, r2c12, r2c13, r2c14, r2c15}, \
+    {r3c0, r3c1, r3c2, r3c3, r3c4, r3c5, r3c6, r3c7, r3c8, r3c9, r3c10, r3c11, r3c12, r3c13, r3c14, r3c15}, \
+  }