v2.2.0 - Prerelease

[Wenn0101]

Changelog:
-add a default Wire for artemis module
-fix low rx causing hangs
-update arduino api to v1.2
-revert i2c change that was causing transfer errors at 100khz
-add SPI_HAS_TRANSACTION define
-(remove additional targets from attached mbed core)

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This discussion was created from the release v2.2.0 - Prerelease.

[Wenn0101]

the SPI_HAS_TRANSACTION define seems to have been fixed twice. i will roll out one of them before release.