Driver: BMP085: Work over the implementation of this driver.

- Use enum classes instead of plain enums,
- Use friend classing for proper data encapsulation,
- remove unnecessary isBusy() call to adapter,
- mode can be set without having to read out the calibration again,
- use endian-aware calibration value conversion.
- fix i2cTask assignment for SoftwareI2c, and
- use more verbose I2cTask values.