Defined the charsets plus a default.

- Also partial cleanup of Marlin_main.cpp with a smidgen of Doxygen.

MSG_NO_MOVE = 'Kein Zug.' > 'Motoren Eingesch.' hat mich grau Haare gekostet.
Die englisch Meldung will sagen - Du kannst jetz am Extruder arbeiten, die
Achsen sind bockiert, die Motoren sperren die Achsen weil sie unter Strom
stehen, weil sie eingeschaltet sind.

to work out that this can't be resumed.

- Also adds a language string for the error.
- Also adds SERIAL_EOL as an alias for SERIAL_ECHOLN(“”)

Should be reading 4 x 4 PID values instead of 4 x 3

Extruder 2 and 3 was swapped

Update ConfigurationStore to always write dummy values for disabled
options, including FWRETRACT, DELTA, and SCARA. Update the EEPROM
version to “V15.” Also fixes a buffer overrun with axis_scaling in
Config_ResetDefault.

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

Also fix analogInputToDigitalPin so it uses proper C hex notation

There’s no need to ask users to uncomment Max Endstop pins when they
have them. These will be set to -1 later if the endstop option is
disabled.

#1405 includes some changes to pins.h for a 4th extruder. This commit
applies those changes. It also deals with a possible problem with
SENSITIVE_PINS.

Hopefully this is helpful to organization and future expansion….

Also fix analogInputToDigitalPin so it uses proper C hex notation

Moved #endif to allow filament settings to print.

Added PIDTEMP dummy write to align EEPROM read/write operation.