Changed UBL_G26_MESH_EDITING to UBL_G26_MESH_VALIDATION
Added UBL_MESH_EDIT_MOVES_Z to prepare for that change (coming next)

- fix broken `M421` due to less-than-careful optimization
- add HOME_AFTER_DEACTIVATE define to advanced config so not everyone has to rehome after steppers are deactivated
- misc. cleanups (remove unused label, unused variables)

UltiPanel was enabled, but technically, it is a REPRAP_DISCOUNT_SMART_CONTROLLER
Either configuration works on the machine.  But we want it 'Right'.

Setup the Proportional Font spacing so columns line up nicer on PronterFace and Repetier Host.

- update example configs

 - rename to PROBING_HEATERS_OFF
 - move heater pausing functionality into thermalManager
   - add variables, pause(), ispaused(), other functions
 - add fan pausing functionality -> PROBING_FANS_OFF
 - add probing_pause() wrapper
 - move pausing into do_homing_move() and do_probe_move() to minimize quiet time and so other probe types can benefit
 - example configs

The Configuration.h file entries for BL-Touch have been updated to:
```cpp
//#define BLTOUCH
//#define BLTOUCH_DELAY 375      // (ms) Enable and increase if needed
//#define BLTOUCH_HEATERS_OFF // if defined the printer's heaters are
turned off during probe event
```

Also setting up Z-Probe on the machine.

Change to support new name GRID_MAX_POINTS_XY
Start UBL at version 1.0 in the CUSTOM_MACHINE_NAME

These are my two 'Nice' machines.  Both are good example machines.  The
FolgerTech i3-2020 is probably the best value kit on the market right
now.  And it has developed a 'Cult Following' of hobbiests.  I'll always
have an up to date Configuration.h file set for it, so it may as well be
an example configuration.

And the gCreate gMax 1.5+ is the best printer I've ever seen that runs
Marlin.  For sure, I'll always have up to the minute Configuration.h
files for this printer also.   I've moved over to using the gMax as my
primary development machine for Marlin.   So...  Besides being a good
machine, it is a nice convienience for me to have this Configuration.h
file as an 'Example'.