Merge branch 'feature/esptool_espefuse_set_flash_voltage' into 'master'

Merge branch 'feature/esptool_espefuse_set_flash_voltage' into 'master'

esptool version bump and new "espefuse.py set_flash voltage" command

* New "espefuse.py set_flash_voltage" command to easily set a fix
  VDD_SDIO regulator voltage (1.8V, 3.3V or disabled).
* Fixes bugs when flashing files with non-4-byte aligned lengths
  (doesn't effect esp-idf image files)
* esptool README improvements
* Detect overlapping files in write_flash
* read_mac now works correctly on ESP32
* Integrates reset fix for older dev boards (formerly the "Windows ESP32R0 reset workaround")

See merge request !481