* UBL G29 -P3.1 mesh fill with distance-weighted least squares fit.

* Back to original -O0 on G29 for now.

Constrain LCD status message rendering

* Misc. Clean Up

Mostly UBL related clean up.
- But fixed a bug in the thermistortables.
- Made G26 more responsive to user aborts.
- Added sanity checks for older name for UBL_MESH_VALIDATION.
- Made G29 P4 able to edit invalidated mesh points
- Restore a reasonable Fade Height for UBL when creating new state information
- Get UBL's Topology Map to look a little bit better
- Make sure the user doesn't see a blank screen when doing Mesh Editing.

* Huh???   GitHub Desktop screwed up!

* get the planner object in scope

* Fix out of scope z_fade_height

* Travis timed out...

I need a change so I can force a new commit and sync.

Fix set_lcd_contrast

Cleanup code, organize & document fastio pin mappings

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

Reference: #6804

Add "live editing" option to LCD menus

Restore current temp accessors to float

G33 updates

Disable PROBE_MANUALLY for UBL

Plus some other UBL tweaks.

Patch LCD code for 5th extruder

Tweak Azteeg X3 PRO _pins.h so Viki2 will work for those without a case light

- add comment explaining that the Panucatt Viki2 wiring diagram uses pin 44

Add `G7` gcode command to move between UBL mesh points

- can be augmented in the future to enable for other leveling systems

Quite simple, but did not want to modify `G1` as the additional checking would slow it down.

Tested & working.

Fix recent regressions, &c.

- 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)