CHANGE, FEATURE, BUGFIX
- Increasing of the access delay for the external EEPROM.
  - At some printers the previous delay was too short and as a result the z-compensation values could not be read/written properly.
- Adding of the "Input Filament" menu entry to the "Quick Settings" menu.
  - This operation can be used in order to input new filament to the extruder.
  - INPUT_FILAMENT_SCRIPT can be used in order to define the exact command sequence for the input of the filament.
- Fine tunning of various settings within Configuration.h:
  - new PID values for the extruder
  - new motor currents
  - correction of a DRV8711 register for better support of higher feedrates
  - ...
- Adding of RF1000_MICRO_STEPS which allows to switch the to-be-used micro steps between 4, 8, 16, 32 and 64.
  - The default value remains at 8 which is equal to the so-far-used micro steps.
  - Most position variables have been changed from short to long in order to support also the higher number of steps.
- The format of the compensation matrix has been changed so that the same compensation matrix can be used for different micro step settings.
  - There is no need anymore to perform a rescan after the to-be-used micro steps have been changed.
- In case the z-stepper was enabled via the hardware buttons it might not have been disabled ever.
- Redefinition of the hardware buttons for the z-direction:
  - In case printing is in progress, these hardware buttons can be used in order to fine-tune the z-position. There is no automatic increasing of the z-speed in case of this mode.
  - In case there is no printing in progress, these hardware buttons behave like the "Position Z" menu.
  - FEATURE_ENABLE_MANUAL_Z_SAFETY has been enabled in order to avoid an accidental overrun of the z-min endstop.
- There was a chance that not all steppers were disabled properly during the restart/reset of the firmware.
- Moving to V 0.91.39 (2014-10-10).