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/algernon/rules.mk

@@ -0,0 +1,43 @@
+BOOTMAGIC_ENABLE=no
+COMMAND_ENABLE=no
+SLEEP_LED_ENABLE=no
+FORCE_NKRO = yes
+DEBUG_ENABLE = no
+CONSOLE_ENABLE = no
+TAP_DANCE_ENABLE = yes
+KEYLOGGER_ENABLE = yes
+UCIS_ENABLE = yes
+MOUSEKEY_ENABLE = no
+
+AUTOLOG_ENABLE = no
+
+ifeq (${FORCE_NKRO},yes)
+OPT_DEFS += -DFORCE_NKRO
+endif
+
+ifeq (${AUTOLOG_ENABLE},yes)
+KEYLOGGER_ENABLE = yes
+OPT_DEFS += -DAUTOLOG_ENABLE
+endif
+
+ifeq (${KEYLOGGER_ENABLE},yes)
+OPT_DEFS += -DKEYLOGGER_ENABLE
+CONSOLE_ENABLE = yes
+endif
+
+OPT_DEFS += -DUSER_PRINT
+
+LAYOUT_ergodox_VERSION = $(shell \
+ if [ -d "${LAYOUT_ergodox_PATH}/.git" ]; then \
+  cd "${LAYOUT_ergodox_PATH}" && git describe --abbrev=6 --dirty --always --tags --match 'v*' 2>/dev/null; \
+ else echo QMK; fi)
+
+LAYOUT_ergodox_BRANCH = $(shell \
+ if [ -d "${LAYOUT_ergodox_PATH}/.git" ]; then \
+  cd "${LAYOUT_ergodox_PATH}"; \
+ fi; \
+ git rev-parse --abbrev-ref HEAD 2>/dev/null)
+
+OPT_DEFS += -DLAYOUT_ergodox_VERSION=\"$(LAYOUT_ergodox_VERSION)\\\#$(LAYOUT_ergodox_BRANCH)\"
+
+