75ms might  be excessive...    But I know people are seeing problems with PronterFace as the client...

Original Mesh Bed Leveling replacement put at top of UBL Menu Options to
help facilitate the removal of the Original Mesh Bed Leveling.

Radar display (and control) of the UBL Interactive Mesh Editing.

* Change all direct changes of ubl.state.active to
  set_bed_leveling_enabled() which handles apply/unapply
  leveling to maintain current_position consistency.

Fix invalidation of UBL mesh to invalid unreachable
  mesh points as well (delta corners).

Fix UBL_DELTA unapply_leveling logic and when
it gets applied, including fade_height changes.

Add optional M114 D for detailed position information,
disabled from compilation by default (M114_DETAIL).

* UBL_DELTA raw and inline kinematics

* UBL planner fall through fix

* consistent variable names

* Cleanup orphaned code and whitespace changes.
Use _O2.

* compile warnings cleanup

* Remove redundant #ifdef condition

* 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.

 - Add crc16 utility function
 - Implement CRC16 for config store, remove old checksum, increment layout version
 - Move UBL mesh store/load to MarlinSettings; increment UBL_VERSION
 - Begin to lay out MAT structure, prototype functions, etc.
 - Rename ubl.state.eeprom_storage_slot to .storage_slot
 - Misc. optimization
 - Cleanup/standardize/improve some messages

This is a work in progress!

UBL on Delta's....     Should be close!    Should not affect any Cartesian printer.

- update example configs

I think I forgot to Sync before I committed last time.   Some UBL
changes did not stick.

Also, update the gMax configuaration.h file so other than unique numbers
and settings, it exactly matches the default configuration.h file.

UBL Clean up.

add BLTouch-related messages in english and (rusty) french;
add missing endstops.h in ultralcd.cpp;
fix misc. compiler warnings;
fix lsf_reset - ZERO macro can't handle a pointer as it would only memset the size of the pointer, not the size of the entire struct

Also...   The memory corruption issue may be fixed.   The GCC compiler
was inlining static functions and this caused the G29() stack frame to
become much larger than the AVR could handle.

* relocated ubl state to config. store:
 * removed a number of ubl state variables and padding which were largely unused - saved 58 bytes of both SRAM and EEPROM;
 * modified ubl sanity_check - no longer checks removed state variables that were otherwise unused, where checking didn't seem to accomplish anything, ultimately;
 * removed pre_initialized state, saving 64 bytes of SRAM;
 * removed automatic saving of UBL state after UBL activation/deactivation;
* consolidated multiple GRID_MAX_POINTS_X/Y to 'Global Leveling' section of EEPROM;
* minor update to G29 Sx notes/instructions;
* renamed mesh load and save parameter to 'slot' from 'm' for clarity;

fix maximum mesh_index_ array size at 16 (15+1);

Pretty much...  The code is in place.  Still more work to do.    But it
has a lot of hooks and variables in other code, so commit and merge
before I pick up a million 'Conflicts'.

As it turns out...   an unsigned int can not go to less than 0,  so the
loop never terminates.

- Make all `unified_bed_leveling` data/methods static
- Move some UBL-related variables into the class
- Replace `map_[xy]_index_to_bed_location` with `mesh_index_to_[xy]pos`