Creates a layouts/ folder for keymaps shared between keyboards (#1609)

* include variables and .h files as pp directives

* start layout compilation

* split ergodoxes up

* don't compile all layouts for everything

* might seg fault

* reset layouts variable

* actually reset layouts

* include rules.mk instead

* remove includes from rules.mk

* update variable setting

* load visualizer from path

* adds some more examples

* adds more layouts

* more boards added

* more boards added

* adds documentation for layouts

* use lowercase names for LAYOUT_

* add layout.json files for each layout

* add community folder, default keymaps for layouts

* touch-up default layouts

* touch-up layouts, some keyboard rules.mk

* update documentation for layouts

* fix up serial/i2c switches

keyboards/preonic/preonic.c

@@ -1,4 +1,4 @@
-#include "preonic.h"
+#include QMK_KEYBOARD_H
 
 #ifdef ONEHAND_ENABLE
 __attribute__ ((weak))

keyboards/preonic/preonic.h

@@ -33,4 +33,6 @@
 	{ k40, k41, k42, k43, k44, k45, k46, k47, k48, k49, k4a, k4b } \
 }
 
+#define LAYOUT_ortho_5x12 PREONIC_GRID
+
 #endif

keyboards/preonic/rules.mk

@@ -67,4 +67,6 @@ RGBLIGHT_ENABLE = no        # Enable WS2812 RGB underlight.
 API_SYSEX_ENABLE = no
 
 # Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
-SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
+SLEEP_LED_ENABLE = no    # Breathing sleep LED during USB suspend
+
+LAYOUTS = ortho_5x12