Add MxSS keyboard (#3335)

* Added basic MxSS support

* Fixed split RSHFT for ISO layouts

* Updated readme.md for MxSS

* Added initial support for individual control of front RGB LEDs

* Changed RGBLED color selection to work using hue and saturation rather than RGB
Added code for LED state change on layer change

* Avoid needing an entire 8 bits to store the brightness value

* Added custom keycodes, along with their handlers

* Added EEPROM storage for front LED config

* Fixed up ability to use QMK Configurator and updated readme.md

* Applied suggested changes from pull request: https://github.com/standard/standard/issues/452

Updated name in license descriptions
Updated layouts to snake case
Corrected mistakes in info.json
Updated layer_colors to a weak attributed array in mxss.c

* Defined a new safe range for custom keycodes in keymap.c

keyboards/mxss/keymaps/default/config.h

@@ -0,0 +1,24 @@
+/* Copyright 2018 Jumail Mundekkat / MxBlue
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef CONFIG_USER_H
+#define CONFIG_USER_H
+
+#include "config_common.h"
+
+// place overrides here
+
+#endif