Fix: current_command_args skips digits at the front

Closes #3245

Fix distribution date

Updated Mesh Bed Leveling

axis_known_position -> axis_homed

Code cleanup around MOTOR_CURRENT_PWM options

In all these cases we want the axis to be homed. If we could have lost
some steps is secondary.

Reenables homing seperate axis with DISABLE_X / DISABLE_Y true.

copy of https://github.com/MarlinFirmware/MarlinDev/pull/199/commits/406992f9dd44655b33dab46e0cb4fd4a29be1695

Also add mbl.z_offset to the EEPROM, bumping the version to V23.

Fix a compiler warning in ultralcd.cpp

Closes #3235. Fix dogm lcd error when FAN_PIN is defined as -1

Further cleanup of comments, partial Doxygen-style

Following up on #3231

Fix spelling

Added GPLv3 header to all Marlin files

PROBABLE ->PROBEABLE
This is follow-up to #3069?

Toshiba Flash Air Wifi SD card support

Enabling servo usage on boards with PWM current control

Use arduino programming protocol by default for sanguino

Fix MELZI_MAKR3D to use correct motherboard

M120/M121 also set endstops non-homing state

Add Menu Items to initiate M303