* I2C is not defined in the reference schematic nor HT-DEV-ESP board, remove definition accordingly
* There is no screen in the the reference schematic nor HT-DEV-ESP board, change definition accordingly
* BUTTON_PIN has a 10 kOhm pullup resistor on HT-DEV-ESP, turning off redundant internal pullup should save some power
* LED is connected to GPIO2 on HT-DEV-ESP and is not inverted, update definition accordingly
* Remove redundant undef lines for LoRa pins
Above changes were built and flashed to my [HT-DEV-ESP_V2 board purchased from Heltec's Taobao store](https://item.taobao.com/item.htm?id=521590063077).
Signed-off-by: Andrew Yong <me@ndoo.sg>
18e69a0906