* add readPort() and some API to 'tmk_core/common/*/gpio.h'
The following macros have been added to gpio.h.
* readPort(port)
* setPortBitInput(port, bit)
* setPortBitInputHigh(port, bit)
* setPortBitOutput(port, bit)
* writePortBitLow(port, bit)
* writePortBitHigh(port, bit)
* add data type 'port_data_t' into gpio.h
* rename qmk_pin to pin