- Fix bug in lcd_control_temperature_menu
- Remove test menu-item left in from multi-line command feature
- Replace literals with translatable strings
- Reduce lcd_preheat code redundancy
- Reduce menu macro redundancy
- Clean up formatting

Last commit before bed.

- Make this work per #1344

- Also apply cleanup for #1514

Slightly better layout for wide screens.

Introduced lcd_strlen() and lcd_strlen_P().
Replaced the old functions where necessary.
Reworked language_ru.h.

Speeded up test for zero length string in cardreader.cpp

- K8200 uses a non-standard RAMPS with Z_ENABLE=63 ??
- Assuming from previous input that 3DRAG is the same.

The `float` keyword should not be on these vars because they conceal
the outer vars, preventing them from obtaining known values before
being passed in `set_bed_level_equation_3pts`. Possibly related to
`Z_RAISE_BETWEEN_PROBING` not functioning.

When probing PCB´s I had the problem that i needed auto-leveling for specific areas (it´s never the same size).
Not much code, but very useful.
Now I use simply G29 L5 R55 F5 B35 P3 to probe a 4x6cm PCB before milling.
I used int for values... might be wrong...
I hope this time I got the right development tree. (tried first with https://github.com/MarlinFirmware/Marlin/pull/1130/commits)

- Auto-detect “switchable” items where possible
- Handle switchable multi-value fields
- Add standard sections to config form
- Add section markers to configurations
- Add value options to configurations
- Remove and re-add fields for loaded configs
- Preserve sections across configs
- Preserve non-added fields
- Style added fields wider & newline by default

Fixed how stepper ISR figure it out when the head (extruder) is going to
Min or Max direction.
Added Homing to Max Endstops.

- Naive implementation, assuming the data sheet pin numbers correspond
to Arduino pin numbers.

- Fetch code now handles github, local, or http: access
- Download button creates a time-stamped inline download
- More complete error messages
- Show warnings when approaching the hourly fetch quota (limit
reloading!)
- Added my test domain (where the _htaccess is deployed)
- `_htaccess` file added to set Access-Control-Allow-Origin “*”
- Marlin logo with css
- Limit selectable areas to avoid annoying selections
- Messages now persist until dismissed
- Default repo for files set to thinkyhead, ‘marlin_configurator’ branch
- Cosmetic changes

Fixed delay-times during Init. REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER won't get initialized on some Boards because delay was to short.

- Make api.github the default source for configurations
- Remove configurations from the configurator
- Continuation and enhancements

Looks like INVERT_E3_DIR was missing in the configuration.h also as I
did a test compile with 4 extruders and Azteeg X3 Pro defined. So I also
added those lines too. Additional formatting to make the comments line
up better in that section.

Include of language_en.h now behind national language.

All "#define MSG_STR_*" now surrounded by #ifndef and #endif.

+ May decrease the workload for feature developers. They may omit to
update all the language files but "language_en.h". When loading _en
first, all new features give some display, but the new in English.

- May throw some additional warnings about redefinition during compile.