Backport override syntax conversion to Lamprey

Per recent discussion in the AGL dev calls, it has been decided to backport the override syntax conversion for compatibility with honister and later Yocto Project to the Lamprey branch, with the goal being to reduce conflicts when backporting changes from the AGL master branch.  Since we are a few months away from updating to what will become Yocto Project kirkstone on master, and the Lamprey branch will likely see extended maintenance due to the app framework replacement work in Marlin, this seems worthwhile to avoid extra effort down the road.