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/jafo/readme.md

@@ -0,0 +1,20 @@
+# ErgoDox EZ "jafo" Configuration
+
+This is a layout based on the ErgoDox Ez default layout, but with some
+customizations I made for my use-case.  I use Linux, vi and the i3 window
+manager, so I made these changes:
+
+- Arrow keys laid out in vi positions in media layer.
+
+- Esc (tap) and Win (held) to the left of A.  i3 uses Win key for navigation
+  and having that be symmetric on the left and right makes it easier.
+
+- Grave accent below equals, I was having a hard time using ~
+
+- Layer 2 switch below the L1 switch, so I can go into a mode where I get
+  arrow keys under my vi motion fingers.
+
+- Making the Ctrl (held) and Esc (tap) on my thumbs symmetric.  Not sure I
+  need that with the Esc left of A and Ctrl on the Z and / keys when held...
+
+![Jafo](https://i.imgur.com/ISEc630.png)