Fan speed and 4th extruder on graphical LCD

- Display fan speed 0-1 as “—“ and 254-255 as “100%”.
- Display 4th extruder instead of the heated bed

Merge latest Development

- Add a span to the edited text line to provide a highlight
- Scroll and highlight for switch checkboxes also
- Clean up initialization
- More API documentation
- Smarter handling of asynchronous file loading during init

- Animate scrolling to the edited item’s position
- Sanity check file drops and show warnings
- Fix form init / refresh on new configuration drop
- Document the API methods that get/set defines

Browsers may not want to load files outside the folder, but they may be
okay with these relative references within the folder.

Fix bad typo in ConfigurationStore.cpp

- When initializing fields use the configuration to determine the format
- Cache the line for each option for fastest string compare / replace
- Add logging levels for debugging

- Specify HTML5
- Allow drag and drop for loading configurations

- A web form with fields for configuration values
- Reads and parses standard config files
- Modifies configurations dynamically in-place

K8200: Example Configuration.h fixed

Example Configuration.h: fixed strange white characters preventing
compilation in lines 1 and 3 - oops

Unified menu selection - by hilighting - made first column avilable

K8200: Example Configurations back in sync and readme update

Example Configurations for K8200 readme.md updated
* readme.md: added description for german umlaut support on LCD

Example Configuration_adv.h for K8200 back in sync
* Configuration_adv.h: rebased and added missing changes for 4th
extruder

Example Configuration.h for K8200 back in sync
* Configuration.h: rebased and added missing changes
* Configuration.h: updated comments for K8200

New function now drops the prechar (select character) and makes the first
column usable for text.
Marking the line is now constantly made by highlighting (reverse).

Replaced selection code in:
lcd_implementation_drawmenu_generic()
_drawmenu_setting_edit_generic()
_drawmenu_sd()

with new function.

Apply some cleanup for recent merge

Apply fix for M600 filament change

Combine 1/(rows+1) with u8g.getHeight() to get rowHeight and just use
that.

Fixes issue #1447 - Overlapping of long descriptions with values.

- Patch from #1453 for delta movement plan
- Fix: Set X with code X instead of adding to X

Reworked bootsplash for DOGM displays another time - saved 1786 bytes

Adjust LCD_WIDTH to make better use of DOGM LCDs 2

Prework for issue #1448 and #1447

Will merge in when pull request #1457 is in.

Replaced calculation to centre bitmap with fixed values.
Saved 20 bytes.

and win another 1694 bytes.

No visible impact.