Apply `ENABLED` / `DISABLED` macros to language-related files.

and translate them to German.

To avoid double definitions.
I prefer to read N for Number not for Nozzle.

And call _temp_error() directly for ERR_MAXTEMP_BED to avoid the only one time use of bed_max_temp_error().

Includes #2156.

Edited the European part of 'ISO10646_CN.fon' to match the existing fonts.
Added Chinese font to make_fonts.bat
Created 'dogm_font_data_ISO10646_CN.h'
Added Chinese to 'language.h'
Added 'language_cn.h' with some minor edits.
Added Chinese font in 'language_en.h' to not fall back to European font.
Added cn to 'Configuration.h'
Changed WIDTH to LCD_PIXEL_WIDTH and HEIGHT to LCD_PIXEL_HEIGHT to have more descriptive names.

In 'dogm_lcd_implementation.h'
Added Chinese Font
Made 1 pixel more room for the larger Chinese font on the status line.
Changed geometry of the 'select bar' by one pixel.
Changed the way the position for values and postcars are set.

* Added MSG_END_HOUR and MSG_END_MINUTE labels to all language files.
* Available translations:
  EN, FR, DE, ES, IT, PT, PT-BR.

Automatic selection was to unflexible.

Updated documentation

Updated language files to new logic and documentation.

Updated bdf2u8g.exe

Added option to set Travel Acceleration (non printing moves).
The M204 options was a non sense (S for printing moves and T for retract
moves).

It has been changed to:
P = Printing moves
R = Retract only (no X, Y, Z) moves
T = Travel (non
printing) moves

I will add this info o G-Code wiki in reprap.org. I also advise to put
this info in Marlin next version changelog.

- 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

Include of language_en.h now behind national language.

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

This won’t reduce the string storage in the end, but it makes the
language files smaller. Also removed remaining unused strings.

* Depending on extruder count, will add menu items for ultralcd to edit
individual PID parameters for each extruder
* Added menu items to each language_xx.h
* Builds OK, but recommend testing with typical LCD

This reverts commit 2b9722f387.

To test/enable, uncomment the #define DELTA_CALIBRATION_MENU in Configuration.h

Breaking up languages.h makes it easier to translate. Using language
codes makes it easier to select a language and sets the naming standard.