.
Now using a completely generic "run" script to build, install, and uninstall
the Fexl system.  Run "./run" to see the options.

This replaces the old "build" script, which contained program-specific data.
The new "run" script automatically analyzes the "src" directory, finding all
the .c files and examining their .h dependencies, and creating an obj/build
script to build the system efficiently.  If obj/build already exists, it uses
that so it doesn't have to do the analysis every time (even though it's very
quick anyway).