Blender Git Loki

Fix: "pchan_name" field in SDNA for names of bone targets for drivers was too short

When all the names in Blender were updated to go from having 32 characters to 64,
the "pchan_name" field in the DriverTarget struct was missed. This meant that if you
had a bone with a suitably long name, it would have been impossible to use values from this
bone in a driver.

The only reason this probably hasn't been discovered yet is because the standard/old depsgraph
doesn't work that well for bones in the same armatures, so setups where this may have
occurred are not that common.

To prevent this problem from happening in future, I've added the standard "MAX_ID_NAME-2"
comment to the comments on each line likely to be impacted by such changes, making it
easier for whoever does a search and replace in future :)