- Add “Level Bed” menu item for auto bed leveling
- Hide the option if homing has not been done yet
- Arrange the Prepare submenu more logically (?)
- Add documentation comments, some white-space
- Apply some coding standards here and there
- Move old encoder multiplier debug option to `ultralcd.cpp`

- Address issue raised in #1961

Centralised beep code to lcd_buzz().
From gcode_M300() and lcd_quick_feedback().

Enforced max. duration for M300 to 5 seconds.

Corrected description in 'Configuration.h'

LCD_FEEDBACK_FREQUENCY_HZ 0 gives now a silent delay of
LCD_FEEDBACK_FREQUENCY_DURATION_MS.

lcdDrawUpdate = 2 helped a lot!

- MENU_ITEM causes lcd_quick_feedback to be called, so only those calls
to `lcd_goto_menu` outside of the `MENU_ITEM` macro need to set the
`feedback` flag when calling `lcd_goto_menu`.

- Use `line_to_current` in place of `plan_buffer_line`

where the hardware is available.
Fix for #1873

The other two devices we use in u8glib have more than only dummy code.
Checked this in the library code.

Squished #1849

Because we now can use utf8 with up to 3 bytes per symbol,
lcd_status_message[] must be 3*LCD_WIDTH wide.
Filling up the message, or cutting to length, are fixed to.

Fix for #1832 about at the end.

In 'if (encoderPastThreshold || LCD_CLICKED)' lcdDrawUpdate was not set.

'lcd_status_update_delay'-loop was not effective in  function
lcd_status_screen().
The loop prevented the update of the status screen but not the displays
update.
Shifted the loop into lcd_update().

This reverts commit 6361404b91.

Shifted condition should still be in.

Result see: https://youtu.be/AEnBzdu9_tk
Dot is moving not so fast -> less executed loops.

Result see: https://www.youtube.com/watch?v=tdu7J0i-c4g
Loop is executed several times per display update.

* Use "G29 S3 Xn Yn Zn.nn" to modify bad probed point manually
* Changed manual Z steps from 0.05 to 0.025 and made brought it to Configuration.h

- Make the default LCD click sound more pleasant
- Fix warnings about bed temperature runaway

This rolls back to commit 06f767d608.

- Some messages should not expire with `PROGRESS_MSG_EXPIRE`.
- Simplify conditional for progress bar with sanity checks.
- Rename `messageTick` to `expireStatusMillis` and make it the expire
time.

Fix for #1460.

Seems to work with only one extruder. Can't test this myself with more.

- Patched up for most included configurations

- Increase the probe offset range to -20…20
- Apply the range limits to the menu item

what caused an extra update of encoderLine most of the time.

I've updated the minimum values from the LCD.
It has been a while that i want to at least fix this.
I have an inductive probe and often i need to set my zOffset to something lower than 0.5.
With the current implementation, the default LCD value is set to 0.5 for some reason.
On my case i need to be able to set it down to 0.0 as my inductive probe can be lower than 0.5.
Before with the LCD we couldn't change this value below 0.5. We had to flash the firmware every time which was painful.
Now we are able to change this value down to 0.0 if needed.
I've also changed the minimum value for Z min acceleration.
In the default configuration it's set to 25 but on the LCD the minimum was 100 which is not coherent.
I've changes the minimum to 10. On this axis, depending on the mechanics/motor drivers we might require very low acceleration, so i guess 10 is somehow realistic.

- Address #1262 by leaving values as set
- Rename `add_homing` to `home_offset`

by updating 'encoderPosition' in END_MENU() line 1.