Firmware rev1: Add compose key (Menu); add macro to type ♡ (requires .XCompose entry)

.XCompose file:
```
include "%L"

<Multi_key> <c> <3> : "♡"
```

qmk_keyboards/binarydiv/eepyboard/rev1/keymaps/default/keymap.c

@@ -19,16 +19,20 @@ enum layer_names {
 enum custom_keycodes {
     // Macro to select the current word (Ctrl-Left, Shift-Ctrl-Right)
     MACRO_SELECT_WORD = SAFE_RANGE,
+
+    // Special characters that require more complicated input
+    MACRO_HEART,
 };
 
+// For keycodes, see QMK docs: https://docs.qmk.fm/keycodes
 const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
     // Base layer
     [L_BASE] = LAYOUT_ortho_6x13(
         KC_ESC,        KC_F1,  KC_F2,   KC_F3,       KC_F4,       KC_F5,    KC_F6,   KC_F7,        KC_F8,        _______,  _______,      _______,         KC_KB_MUTE,
         KC_GRAVE,      KC_1,   KC_2,    KC_3,        KC_4,        KC_5,     KC_6,    KC_7,         KC_8,         KC_9,     KC_0,         KC_MINUS,        KC_EQUAL,
         KC_TAB,        KC_Q,   KC_W,    KC_E,        KC_R,        KC_T,     KC_Y,    KC_U,         KC_I,         KC_O,     KC_P,         KC_LEFT_BRACKET, KC_RIGHT_BRACKET,
-        KC_ESC,        KC_A,    KC_S,    KC_D,        KC_F,        KC_G,     KC_H,    KC_J,         KC_K,         KC_L,     KC_SEMICOLON, KC_QUOTE,        KC_BACKSLASH,
+        KC_APP,        KC_A,   KC_S,    KC_D,        KC_F,        KC_G,     KC_H,    KC_J,         KC_K,         KC_L,     KC_SEMICOLON, KC_QUOTE,        KC_BACKSLASH,
-        KC_LEFT_SHIFT, KC_HOME, KC_Z,    KC_X,        KC_C,        KC_V,     KC_B,    KC_N,         KC_M,         KC_COMMA, KC_DOT,       KC_SLASH,        KC_RIGHT_SHIFT,
+        KC_LEFT_SHIFT, KC_ESC, KC_Z,    KC_X,        KC_C,        KC_V,     KC_B,    KC_N,         KC_M,         KC_COMMA, KC_DOT,       KC_SLASH,        KC_RIGHT_SHIFT,
         KC_LEFT_CTRL,  KC_END, KC_LGUI, KC_LEFT_ALT, OSL(L_CODE), KC_SPACE, _______, KC_BACKSPACE, KC_RIGHT_ALT, KC_ENTER, KC_DELETE,    MO(L_FN),        KC_RIGHT_CTRL
     ),
 
@@ -38,7 +42,7 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
         KC_ESC,  KC_F1,         KC_F2,             KC_F3,          KC_F4,       KC_F5,    KC_F6,   KC_F7,         KC_F8,           KC_F9,               KC_F10,               KC_F11,  KC_F12,
         _______, KC_HOME,       KC_UP,             KC_END,         KC_PGUP,     _______,  _______, KC_UNDERSCORE, KC_EQUAL,        KC_LEFT_BRACKET,     KC_RIGHT_BRACKET,     _______, _______,
         _______, KC_LEFT,       KC_DOWN,           KC_RIGHT,       KC_PGDN,     _______,  _______, KC_MINUS,      KC_PLUS,         KC_LEFT_CURLY_BRACE, KC_RIGHT_CURLY_BRACE, _______, _______,
-        _______, LCTL(KC_LEFT), MACRO_SELECT_WORD, LCTL(KC_RIGHT), KC_ENTER, _______, _______, _______,       _______,         _______,             _______,              _______, _______,
+        _______, LCTL(KC_LEFT), MACRO_SELECT_WORD, LCTL(KC_RIGHT), MACRO_HEART, KC_ENTER, _______, _______,       _______,         _______,             _______,              _______, _______,
         _______, _______,       _______,           _______,        _______,     _______,  _______, _______,       _______,         _______,             _______,              _______, _______
     ),
 
@@ -72,6 +76,9 @@ const uint16_t PROGMEM encoder_map[][NUM_ENCODERS][NUM_DIRECTIONS] = {
 #endif
 
 bool process_record_user(uint16_t keycode, keyrecord_t *record) {
+    // Store the current modifier state in the variable for later reference
+    uint8_t mod_state = get_mods();
+
     switch (keycode) {
         case MACRO_SELECT_WORD:
             // Run macro when keycode is pressed
@@ -80,6 +87,14 @@ bool process_record_user(uint16_t keycode, keyrecord_t *record) {
                 SEND_STRING(SS_LCTL(SS_TAP(X_LEFT)) SS_LSFT(SS_LCTL(SS_TAP(X_RIGHT))));
             }
             break;
+
+        case MACRO_HEART:
+            if (record->event.pressed) {
+                // Type a outlined heart via X11 Compose key (with custom mappings)
+                del_mods(MOD_MASK_SHIFT);
+                SEND_STRING(SS_TAP(X_APP) "c3");
+                set_mods(mod_state);
+            }
     }
     return true;
 }