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

layouts/community/ergodox/alphadox/rules.mk

@@ -0,0 +1,15 @@
+BOOTMAGIC_ENABLE = no  # Virtual DIP switch configuration(+1000)
+MOUSEKEY_ENABLE  = no  # Mouse keys(+4700)
+EXTRAKEY_ENABLE  = yes # Audio control and System control(+450)
+CONSOLE_ENABLE   = no  # Console for debug(+400)
+COMMAND_ENABLE   = no  # Commands for debug and configuration
+NKRO_ENABLE      = yes # Nkey Rollover - if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ # nkro-doesnt-work
+BACKLIGHT_ENABLE = no  # Enable keyboard backlight functionality
+MIDI_ENABLE      = no  # MIDI controls
+AUDIO_ENABLE     = no  # Audio output on port C6
+UNICODE_ENABLE   = no  # Unicode
+BLUETOOTH_ENABLE = no  # Enable Bluetooth with the Adafruit EZ-Key HID
+RGBLIGHT_ENABLE  = no  # Enable WS2812 RGB underlight.  Do not enable this with audio at the same time.
+SLEEP_LED_ENABLE = no  # Breathing sleep LED during USB suspend
+
+