* Update tachometer.cpp
Initial implementation of E30 M3 Tach output solution #907, unit_test plus debugging next
* tacho unit tests
First successfull unit test for tachometer
* RAM adjustment so it would link
* refactoring tacho, broken!
* starting to make some progress...still fails after a few seconds
* Rework with SW PWM
* Update after code review
* unit_test update
* First working unit_test
* Update .gitignore
* Update engine_controller.cpp
* Update engine_controller.cpp
* Update tachometer.h
* Update test_tacho.cpp
Co-authored-by: rusefi <rusefi@users.noreply.github.com>