Various fixes. Changed stm32.h to remove compile warnings. Changed Wire files to make Wire compile with I2CDev by addition of BUFFER_LENGTH definition, and fixed issue that prevented I2CScanner from working, - by changes in WireBase.cpp, Wire.cpp. Also fixed issue with SCL and SDA pin assignments being the reverse of hardware I2C - to enable future upgrades to Hardware I2C on the same pins, i.e PB6 and PB6 I2C channel 1