Changes only affect UBL.  Everything else is left alone.

See if this has any deleterious effect on motion planning by slicers that inser their own jerk and acceleration controls. The problem I see is that these settings can take effect on blocks already in the planner, and the only way around this would be to shadow these settings in planner blocks and use the shadowed settings in the planner.

* Encapsulate common LCD code in a singleton
* Depend more UBL code on UBL_DEVEL_DEBUGGING
  - Since most users don't need the debugging on at all times, this helps reduce the default build size for UBL by over 2K, a little closer to fitting on 128K boards.

* Make lcd_quick_feedback argument optional
* Add click_to_cancel option to wait_for_hotend/bed
* Have G26 use the active nozzle and wait_for_hotend/bed
* Use wait_for_release in UBL G29
* Add 'T' parameter to G26 for an initial tool-change

Fix #12362

In reference to https://github.com/MarlinFirmware/Marlin/pull/12098#issuecomment-436231690

* Followup to LCD_TIMEOUT_TO_STATUS=0
* Make continuous purge screen fit 20x4
* Unify purge message modes
* Preserve last-set pause header mode

In reference to #11000

Fix #11522

Addressing #11271

- The documentation is correct. The code was wrong.

* Apply #pragma once in headers
* Adjust some thermistors formatting
* Misc cleanup and formatting

* Add parser.seen for multiple parameters
* Fix M666, use !seen for report
* Synchronize on M204, M205

- Drop `pgm_read_*_near` and let headers choose.
- Define `USE_EXECUTE_COMMANDS_IMMEDIATE` as a conditional.
- Add `process_subcommands_now` for SRAM-based commands.

- Followup fixes for menu refactor
- Fix TMC sanity checks, unused var warnings

- Remove `print_job_timer.stop()` from `disable_all_heaters`
- Call `print_job_timer.stop()` for relevant `disable_all_heaters()`.
- Split up `kill()` for watchdog interrupt safety

* Universal tool-change Z lift
* Add TOOLCHANGE_ZRAISE to example configs
* Park/unpark changes to example configs
* Implement DEBUG_DXC_MODE

- Add methods to access print counter data
- Clean up some inconsistent method names
- Clear lcd status after filament change
- Implement `lcd_reset_status` so it works like UltraLCD