rs: code friendly keymap for preonic, iris and my preonic clone (#4303)

I worked on those keymap to simplify the use of 60% keyboards for
coders. Instead of trying to mimic planck, this keymap remove
raise/lower layer complexity and keep some important sign keys for coder
in the upper right side pretty much the same way as they are on a full
keyboard.

A karabiner configuration is also provided to mimic most of the keymap
features on the macbook internal keyboard for when you are forced to use
it.

keyboards/handwired/rs60/rs60.h

@@ -0,0 +1,36 @@
+/*
+Copyright 2018 QMK Community
+
+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/>.
+*/
+#pragma once
+
+#include "quantum.h"
+
+#define LAYOUT( \
+	k00, k01, k02, k03, k04, k05, k06, k07, k08, k09, k0a, k0b, \
+	k10, k11, k12, k13, k14, k15, k16, k17, k18, k19, k1a, k1b, \
+	k20, k21, k22, k23, k24, k25, k26, k27, k28, k29, k2a, k2b, \
+	k30, k31, k32, k33, k34, k35, k36, k37, k38, k39, k3a, k3b, \
+	k40, k41, k42, k43, k44, k45, k46, k47, k48, k49, k4a, k4b \
+) \
+{ \
+	{ k00, k01, k02, k03, k04, k05, k06, k07, k08, k09, k0a, k0b }, \
+	{ k10, k11, k12, k13, k14, k15, k16, k17, k18, k19, k1a, k1b }, \
+	{ k20, k21, k22, k23, k24, k25, k26, k27, k28, k29, k2a, k2b }, \
+	{ k30, k31, k32, k33, k34, k35, k36, k37, k38, k39, k3a, k3b }, \
+	{ k40, k41, k42, k43, k44, k45, k46, k47, k48, k49, k4a, k4b } \
+}
+
+#define LAYOUT_ortho_5x12 LAYOUT