Device generics and cleanup of bme280 mocking

What's Changed

• Merge BME280Mock into BME280 struct by @rustyeddy in #6

Full Changelog: v0.0.2...v0.0.3

Device Generics.

What's Changed

• Created generic vpio driver to allow running on non-gpio OS by @rustyeddy in #5

Full Changelog: v0.0.2...v0.0.3