FIX: Accomodate new meaning of PROJECT_SOURCE_DIR

Due to Slicer commit r22038, the module stopped compiling.  Got rid
of the superfluous BuildMacros which was being included in a now
incorrect path.
FIX/ENH: Update tests to match latest CLI Template structure
FIX: add missing test property line
FIX: enable testing for superbuild
COMP: All building for superbuild other than Slicer

When building ukf from within BRAINS, some paths were missing.
PERF: Forcing const correctness and using references rather than copies

Some profiling indicated that 17% of time of a critical path function was
being spent unnecessarily copying matricies that should have been const
and therefore a reference into the original was sufficient.
STYLE: Remove compiler warnings

unnecessary const on return warning
shadow variable warning