This is an initial cut for feedback.
Chamber temperature is currently reported along with hot end and bed
temperatures to serial. The format is just like that used for hot end
and bed temperatures, but using 'C' prefix. As there is no heater,
target is always 0. Is this appropriate, is there a better way to report
chamber temperatures?
Chamber temperatures are not reported on the LCD in any way.
When auto chamber fan is enabled, it currently just uses the same
temperature threshold as the other auto controlled fans.
As the chamber temperature is not connected to any heater, it doesn't
undergo mintemp/maxtemp monitoring. This would need to change in the
future if chamber heating became a feature.
There is significant downside to breaking up the long line segments on UBL Cartesian machines via the SEGMENT_LEVELED_MOVES mechanism. It adds a lot of extra computation but worse... It cuts out all of UBL's off mesh Z-Height correction checks. There have been a large number of people complaining about the nozzle going to infinity or crashing into the bed lately. They are being caused by
```
void unified_bed_leveling::line_to_destination_cartesian()
```
not watching over the segments being queued up for movement.
The changes to ultralcd.cpp for is_lcd_clicked() did not encompass the
full functionality of UBL's G29 P1, P2 and P4. It also broke G26's
ability to abort in several of its phases.
This is the first pass at fixing the problem. It has been tested for
correctness for several hours but more testing needs to be done.
There may be a few follow up patches to finish covering all the corner
cases, but right now I need to merge this before any conflicts show up.
Some of these changes will need to be moved over to the bugfix-v2.0.0
branch. That will happen a few days from now.
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.
