Merge pull request simplefoc#318 from simplefoc/dev

PR for 2.3.1 release

Merge branch 'master' of github.com:askuric/Arduino-FOC

minDeltaT to min_elapsed_time

readme update release

Merge pull request simplefoc#151 from simplefoc/dev

release v2.2.1

fix typo in css

Annoying pullup struct rename from EXTERN/INTERN to USE_EXTERN/USE_IN…

…TERN

merge dev -v 2.1

collab links

readme v2.0.1