ADE7753

Work in progress, needs cleanup and testing on other platforms.

Now working with esp8266 all types changed since esp is 32 bits.

WARNING! If using this library with esp8266 change SPI mode to 3 since arduino core for esp8266 has an error in SPI.cpp or do this:esp8266/Arduino#2416

Interfaces with ADE7753 single phase energy meter IC.

###Reads:

*Voltage
*Current
*Frequency
*Energy
*Real power
*Reactive power
*Apparent power
*IC temperature