* GPIO refactoring
GPIO now using ESP-IDF API on all chips.
LEDC interrupt fix removed - no longer needed.
Edited pins_arduino.h in variants according to changes in gpio.
* Edited analog channels functions
* Add default pin mapping for Serial1 and Serial2
* Default pin remap on wESP32
Improved default pin mapping for I2C0 and UART1 to avoid issues
with programming.
SDA0 was on IO2 but IO2 needs to be pulled low on reset to enable
serial programming, which conflicts with I2C pull-ups.
RX1 was on IO12, idle UART level is high which conflicts with
IO12 needing to be low on reset to select correct 3.3V flash
voltage.
New mappings:
SDA0 on IO15
RX1 on IO13
TX1 on IO12
