Cleaning up root directory files; map-index performance enhancement, index api cleanup, ensure transaction fix, alpha quality documentation draft

Removed config.lisp and all Makefile related build options.  The build is
now entirely driven from the elephant.asd and ele-bdb.asd files with a
simple user customization file, config.sexp, that should be copied to
my-config.sexp and customized to the user's environment.  Thanks to
pinterface for the initial patch supporting this approach.  Foreign
library loading is also controlled from the asd files now at system
load time rather than at compile time.