Backlight abstraction and other changes (#439)

* redoes matrix pins, abstracts backlight code for B5,6,7

* slimming down keyboard stuff, backlight breathing implemented

* don't call backlight init when no pin

* cleans up user/kb/quantum calls, keyboard files

* fix pvc atomic

* replaces CHANNEL with correct var in breathing

* removes .hexs, updates readmes, updates template

* cleans-up clueboards, readmes to lowercase

* updates readme

keyboards/atomic/keymaps/pvc/config.h

@@ -46,6 +46,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define MATRIX_COL_PINS { F1, F0, B0, C7, F4, F5, F6, F7, D4, D6, B4, D7, D3, D2, D1 }
 #define UNUSED_PINS
 
+#define BACKLIGHT_PIN B7
+#define BACKLIGHT_BREATHING
+
 /* COL2ROW or ROW2COL */
 #define DIODE_DIRECTION COL2ROW