add dummy grib api files
add test, still doesn't build.  incubation
incubation
Merge remote-tracking branch 'upstream/trunk' into trunk
add viewshed calculation
add gitignore
add implementation for viewshed
fix windows nmake build.
silence nmake warnings
little documentation
Merge remote-tracking branch 'upstream/trunk' into trunk
revert accidental change
remove unnecessary check
add too high flag to stop trig calculations
rename to follow conventions better
fix float.h inclusion
rm redundant gitignore.
implement additional height for towers or other structures
Merge remote-tracking branch 'upstream/trunk' into trunk
Merge remote-tracking branch 'upstream/trunk' into trunk