Added Wire library wrapper and merged with I2C_Detector

I kept finding myself writing Wire library wrapper functions in my other libraries to simultaneously support bit banged I2C as well as hardware I2C, so I decided to incorporate that logic here. By specifying GPIO SDA/SCL pins of -1, it will use the Wire library. Any other values will use those pin numbers to bit-bang the protocol. I also incorporated my I2C_Detector logic in the library to scan and recognize (currently 25) different common I2C devices. This allows your projects to find and activate devices without having to know their addresses. I find this especially useful when I test I2C sensors and don't connect anything to the address selection bits. I can just find them and start using them in my code.