Imported I2C library by DSS Circuits
Added I2C test sketch
Made I2C read/write prototypes consistent, removed unwanted functions
Made I2C functions static to save constructor/instantiation
Major formatting changes to I2C library
Removed unwanted I2C pullup function
Defined constants for I2C timeout error codes
Harmonised/shortened I2C functions parameters
Defined I2C speed and timeout as constants
Changed I2C timeout from milliseconds to microseconds
Added functions to swap endianness
Added MPU6050 library and test sketch
Added HMC5883L library and test sketch
Added a sketch to test different ways to make variables read-only
Added BMP085 library and test sketch
Removed sketches no longer used