Consistent fabian layouts for amj40, let's split, planck and xd75 (#1812)

* slight modifier changes; added plover and reusing jack's default planck keymap as the basis

* space is not shift when held anymore

* added fabian layout (based on jack's default)

* changed fabian layout (based on jack's default)

* changed fabian layout (based on jack's default)

keyboards/planck/keymaps/fabian/config.h

@@ -0,0 +1,42 @@
+#ifndef CONFIG_USER_H
+#define CONFIG_USER_H
+
+#include "../../config.h"
+
+#ifdef AUDIO_ENABLE
+    #define STARTUP_SONG SONG(PLANCK_SOUND)
+    // #define STARTUP_SONG SONG(NO_SOUND)
+
+    #define DEFAULT_LAYER_SONGS { SONG(QWERTY_SOUND), \
+                                  SONG(COLEMAK_SOUND), \
+                                  SONG(DVORAK_SOUND) \
+                                }
+#endif
+
+#define MUSIC_MASK (keycode != KC_NO)
+
+/*
+ * MIDI options
+ */
+
+/* Prevent use of disabled MIDI features in the keymap */
+//#define MIDI_ENABLE_STRICT 1
+
+/* enable basic MIDI features:
+   - MIDI notes can be sent when in Music mode is on
+*/
+                                
+#define MIDI_BASIC
+
+/* enable advanced MIDI features:
+   - MIDI notes can be added to the keymap
+   - Octave shift and transpose
+   - Virtual sustain, portamento, and modulation wheel
+   - etc.
+*/
+//#define MIDI_ADVANCED
+
+/* override number of MIDI tone keycodes (each octave adds 12 keycodes and allocates 12 bytes) */
+//#define MIDI_TONE_KEYCODE_OCTAVES 2
+
+#endif