Merge branch 'SAV-MkI_merge' into Development

Tested for SAV MKI and SAV 3D LCD on lewihe.

503 fwretract dev branch

- Fixed issue when BAL area probing is shorter than it should be for
grid probing
- Warning when BAL activated with Delta Kinematics
- Fix XY_TRAVEL_SPEED when homing Z axis

Consider negative Z Offsets when auto bed leveling is active

Fixed BABYSTEPPING feature

Fixes #1069.  Added "auto fan" checks to PID_autotune.

 temperature.cpp: Add Conditional Integration to prevent excessive integral windup 

Move initialization of errormagic[] and echomagic[] to Marlin_main.cpp

LCD Progress Bar

Current defaults are all 255.  If it makes sense to reduce them, they should come down together, and
be in a  PID_INTEGRAL_DRIVE_MAX <= PID_MAX <- BANG_MAX relationship.

getting even with v1

Moved PSTR() macro to correct place which was causing the " initializer fails to determine size of '__c' " when attempting to compile with BABYSTEPPING enabled.

Clarification and markdown for boelle notes

Merge pull request #1213 from ErikZalm/Marlin_v1

Merge pull request #1214 from ErikZalm/Marlin_v1

added note about stale branches

added note about stale branches