Allow negative retract values in the LCD

Add description for choice of DEFAULT_DUAL_X_CARRIAGE_MODE

Replace "+mm" with "mm." Allow negative recover-swap length.

- Japanese and Chinese still need update

Support for M335 case light "no case light"

FILAMENT_CHANGE_FEATURE allowed in idle mode

Fix various LCD-related issues

Throw an error for gcc before 4.7

Have bed leveling status output current status, not requested.

Fix size

Optimize handling of block_buffer_runtime()

Split up thermistor tables

This can already be done via G-Code, so adding the capability to the LCD should be straight forward.

millis_t is long - divisions take for ever.

Return a kind of millisecond instead of microsecond -
divided by 1024 instead of 1000 for speed. (2.4% error)

That does not matter because block_buffer_runtime is
already a too short estimation.
Shrink the return-type.

Report EEPROM data size, not final index

Fix size for writeData and readData.
For bilinear grid 11 x 11 for example, size is 4 (float) x 11 x 11 = 484. uint8_t max is 255.

Update Japanese translation

Update for translations language_pl.h

Save Bed Leveling to EEPROM

Fix for the PR #5255 (Case light menu (3rd attempt))

Remove unnecessary tabs and spaces