Defer expansion of imported library names.

This uses the GNU Make "secondexpansion" facility to defer
expansion of the names of external libraries so that .mak
files included earlier can depend on libraries whose paths
are defined by .mak files included later.
Merge remote-tracking branch 'tc-live/development' into development
Strawman start for Requirements for Matrix and Position
Initial movement toward Matrix/ColVec templates and Position class
Write missing doxygen blocks.