This is a non-intuitive change.   @oldmcg says in this post https://github.com/MarlinFirmware/Marlin/issues/7572#issuecomment-340641207 that using DELTA_PRINTABLE_RADIUS is better than DELTA_PROBABLE_RADIUS for setting the probe limits.   This is because the automatic probe code checks all locations for being reachable by the probe prior to doing the probe.

Based on #8426

2.0.x E0 auto fan fixes for LP1768

[2.0] Fix Filament Width Sensor LCD display

Fixes #7978

[2.0] Add OV() macro for use in thermistor tables

[2.0.x] Fix Software Fan PWM

[2.0] Fix 'M32 P' subroutines

[2.0] Fix parser value handling

[2.0] Add M114_DETAIL to Configuration_adv.h

[2.0] Fix up REPRAPWORLD_KEYPAD defines

[2.0] Move test extrusion options under G26

[2.0] Support for Extrudrboard in Printrboard Rev.F

[2.0] Update Travis CI, fix compiler warnings

As modified in #8395

[2.0] Improve and clarify M428 code

* Fix some 8-bit Teensyduino compile warnings

-Override Teensyduino legacy NOT_A_PIN 127 define
-some fixups for Printrboard_RevF pins

* Proper cleanup of Printrboard Rev.F pins

* Apply LCD fixes to Printrboard v1

[2.0] Remove offsets from soft endstops, tool change

[2.0] Use do_blocking_move_to where possible

[2.0.x] Normalize load/unload length in M600

[2.0.x] PROBE_SELECTED etc.