* 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;
This data corruption problem is very difficult. Just changing the code
a little bit changes whether the problem even happens and what is
affected. I need these changes in the main branch so I can operate with
the extra debug code always available and turned on.
Everything is setup such that if M100 is turned off or DEBUG(ECHO) is
turned off, the code is not affected. M100 has been made a little bit
more inteligent so it can display the serial command buffers in a more
meaningful way (because the data corruption seems to often times end up
in that area).
- On `DELTA` the `M665 H` option supplants `M206`
- On `DELTA` `NO_WORKSPACE_OFFSETS` only reverts `G92` behavior
- Spawn 4 conditionals based on `NO_WORKSPACE_OFFSETS`
- Optimize coordinate space conversion for `DELTA` workspace
- To keep EEPROM version, retain `home_offset[XYZ]`, just ignore XY
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make changes requested by reviewers
===============================================
add M43 test to Travis, fix EOL, remove trailing spaces
