* Clean up Temperature PID
* Improve EEPROM read/write/validate
* Group `SINGLENOZZLE` saved settings
* Group planner saved settings
* Group filament change saved settings
* Group skew saved settings
* Group `FWRETRACT` saved settings
Updating I2C position encoders to enable babystepping and Babystep XY when using the ecm microstep correction method. Also changed default method to ECM microstep.
* [New Feature] I2C position encoder support
I plan to continue improving/cleaning this up, as there areas that need work.
* let the cleanups begin.
* progress
* more progress
* comments, rename files, etc.
* clean
* Cleanups per thinkyhead
* a few more cleanups
* cleanups, bugfixes, etc.
* remove unnecessary passes_test(), additional cleanups/optimizations
* cleanups
* misc.
* Fix up I2CPEM.init() and a few other things.
* organize, fix, rename, etc.
* more optimization
* a few more tweaks