- For better encapsulation add inlines for each prepare_move type
- Move controllerFan vars inside the function as statics
- Some formatting cleanup
- Rename `ClearToSend` as `ok_to_send`

- create sled pin definition
- G28 Works with sled

- Make thermal protection for all hotends and/or bed into simple
switches
- Now enable `WATCH_TEMP_PERIOD` when `THERMAL_PROTECTION_HOTENDS` is
enabled
- Move detailed thermal parameters to `Configuration_adv.h`
- Add sanity checks to warn about old configurations
- Change `WATCH_TEMP_PERIOD` to seconds instead of milliseconds

ok N(linenumber) P(bufferremaining)
the host can use this to send the data much faster.

Some pseudo code:
If (bufferremaining > 0)  send command
## as long there is free buffer send command

Also
if (linenumber > lastsend - bufferremaining) send command
## as long last linenumber received is bigger than lastsend (host) - last bufferremaining received

Persistent homing message.
Message was declared as an alert, therefore it was persistent.
Updated to message.

This reverts the changes done to the error message for line number mismatches done in commit d43cc2dd5f

Servo.cpp and Servo.h were changed to lowercase in Makefile but not their actual filenames.

- Also move audio feedback into the command
- Added shorthand for `lcd_buzz` availability

Add `sync_plan_position()` after `axis_is_at_home(axis)` to keep the
planner position in sync when homing.

This makes `M421` more amenable for irregular matrices

Corrected "servo.h" to "Servo.h" because of the updated filename.

This addresses comments in #1956 and #1079. In particular, this is useful
when both endstops are stationary on a CoreXY system, and the Y axis needs
to be homed before the X so the flags are aligned.

With these changes the output of `M503 S0` is all you need to restore
the EEPROM. Building on this it is straightforward to save and restore
the EEPROM state using the SD card or external GCode file.

- Added `M145` to set “heatup states” for the LCD menu
- Added `M420` to toggle Mesh Bed Leveling
- Added `M421` to set a single Mesh coordinate
- Extended `Config_PrintSettings` with added M codes
- Cleaned up some comments here and there

- Add `M111` as a standard option to set the debug level
- Implement `DEBUG_ECHO` in `process_commands`
- Other debug levels (e.g., `DEBUG_DRYRUN`) need more work

- Address issue raised in #1961