Add CLKPIN/DATAPIN to PIO override (as suggested in #1109)

platformio_override.ini.example

@@ -25,6 +25,9 @@ build_flags = ${common.build_flags_esp8266}
 ;   -D USE_APA102
 ;   -D USE_WS2801
 ;   -D USE_LPD8806
+; PIN defines for 2 wire LEDs
+;   -D CLKPIN=0
+;   -D DATAPIN=2
 ; to drive analog LED strips (aka 5050), uncomment the following
 ; PWM pins 5,12,13,15 are used with Magic Home LED Controller (default)
 ;   -D WLED_USE_ANALOG_LEDS