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/swedish/readme.md

@@ -0,0 +1,36 @@
+# Swedish (sv_SE) Qwerty layout for ErgoDox EZ, based on the Default configuration
+
+*NOTE:* it might still be desirable to set the software layout to sv_SE in your
+OS.
+
+Remind me and I'll provide a picture of the layout.
+
+I have tried making this as close of a match I could between the [default
+ErgoDox EZ configuration](https://ergodox-ez.com/pages/our-firmware) and a
+standard Swedish Qwerty layout.
+
+## Notable differences from default:
+
+* There are three special character buttons (acute accent, circumflex/tilde and
+  apostrophe/asterisk) that don't have any buttons to map to naturally. I've put
+  these at other places:
+
+    * Acute accent (´) can be found in the lower left corner, conveniently
+      placed to reach for making an é.
+
+    * Apostrophe (') was put in the lower left corner, close to acute accent.
+
+    * Circumflex (^) and asterisk (*) was placed in the lower right corner.
+
+    * Tilde (~) and diaeresis (¨) I couldn't find a good place for, so I left
+      those out. I could only get the buttons to produce a single one of the
+      characters. How can I get it to work properly?
+
+* The Alt button on right thumb was exchanged for AltGr (RAlt).
+
+* I changed the backslash in the numpad (layer 1) for a minus. Thought it was
+  more sensible.
+
+* I didn't find a good place for the "<>|" button, so that one was left out.
+  That is a problem that really needs to be resolved. Pipe can be found on layer
+  one, however.