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/supercoder/readme.md

@@ -0,0 +1,29 @@
+SuperCoder 2000 layout for the ErgoDox
+==================================================
+
+![SuperCoder 2000](https://i.imgur.com/6dcU9VY.jpg)
+
+Ever found yourself in need of entering binary codes rapidly? Ever wanted to use
+all ten fingers to do so? Ever felt your SuperCoder 2000 too limiting, by only
+having three buttons? We heard you! With this layout for the ErgoDox EZ, you
+will be able to tap in binary at an unparalleled speed and accuracy! Efficiency
+never seen before!
+
+Behold the Ultimate SuperCoder 2000 layout!
+
+![SuperCoder layout](https://i.imgur.com/Ymzlr9G.png)
+
+### To use it...
+
+To use this piece of top quality engineering, you can either
+[download the hex file][hex] we have prepared for you, or you can compile it on
+your own:
+
+ [hex]: https://raw.githubusercontent.com/algernon/ergodox-supercoder/master/supercoder.hex
+
+```
+$ git clone https://github.com/qmk/qmk_firmware.git
+$ cd qmk_firmware/keyboards/ergodox
+$ git clone https://github.com/algernon/ergodox-supercoder.git keymaps/supercoder
+$ make LAYOUT_ergodox=supercoder
+```