point2dem: Rename DEMError to IntersectionErr

As it is not the DEM's error, it is actually the intersection error
between the 2 rays.
all: This is ASP 2.1
m4: AM_CONFIG_HEADER is obsolete
examples: MOC mapproject correlation search range has changed.

Our fixed search range no longer applies. Maybe ISIS changed it's map
projection result or the jigsaw suddenly got better? Doesn't matter
anyways we'll just let automatic do it's magic.
git: ignore new output from Gtest
Stereo in a subregion: Minor wording change
Minor variable name and other cleanup