Add support for Wire library for ESP-01

[hibikiledo]

Problem

When using the library with ESP-01, the current signatures for begin() doesn't allow users to specify SDA and SCL pins. According to Wire library in Arduino core for ESP8266, when calling to Wire.begin(), it defaults to 4(SDA) and 5(SCL) which ESP-01 doesn't expose such pins.

Proposed solution

I create another signature for begin() which allows users to pass in SDA and SCL pin numbers. The pin numbers are passed to Wire.begin(int sda, int scl).

#ifdef ESP8266
    void begin(uint8_t addr, uint8_t sda, uint8_t sdc);
#endif

Tested

The modified library has been tested and proved to be working. I am currently using the modified library to control relays from MCP23017 I/O ports.

[spotlesscoder]

I need this. Any chance of this getting merged?

[nicocesar]

Oh man... trying to automate all my pipeline I bumped into this,
Can we just merge this? it works.

[ladyada]

hi we will not merge as this is best fixed by espressif - please comment here to request they add a function to do it
espressif/arduino-esp32#3779

[caternuson]

Closing. See issue linked above.