Only measure and store filament width when E is going forward.

Redo of #3268 by @jbrazio

Following up on #3231

Addressing #2773

Redo of #2939 rebased against RCBugFix

Introduce additional variable axis_homed to replace axix_known_position
when the coordinate display should indicate the axis is not homed.
This is to distinguish between "not homed" and "inexact position possible
because stepper was disabled".

# Conflicts:
#	Marlin/ultralcd_implementation_hitachi_HD44780.h
solved

Make the output of M105 more similar to Repetier.
Make the text-print pert of M105 an extra function to make it reusable. `print_heaterstates()`
Use `print_heaterstates()` in M019, M190 and M303

Keep "astyled" reformatting

With the introduction of the #if ENABLED(…)

reads better than

* Fix a couple of renames omission and macro expansion errors.

- For some reason it’s easy to forget what BT stands for, but it
doesn’t need an abbreviation.

The compiler may be able to optimize if it knows an array won’t be
changing.

Note that newer versions of the IDE can still
be made to support compilation for the older boards.

replace extruder_multiply with extruder_multiplier
like feedrate_multiplier or volumetric_multiplier