Fixed problem where the safety-height value was not being converted to the correct units value.  i.e. it was a PropertyDouble rather than a PropertyLength.  This should solve Issue 192
Fixed problem where the safety-height value was not being converted to the correct units value.  i.e. it was a PropertyDouble rather than a PropertyLength.  This should solve Issue 192

danheeks/heekscnc,danheeks/heekscnc,danheeks/heekscnc,danheeks/heekscnc