~ allow conditional inclusion/exclusion of sources

~ conditional loading of plugins (by command line goals)

~ rewrite configure plugin. rewrite dc_deps

~ generate makefile (as good as possible)

~ provide script for calling populate with systemwide installation.

~ add support for bigloo

- add support for gambit

~ write documentation

~ add copyright notices everywhere

~ add =readme, =license files

~ dist-clean target should remove everything except listed in =sources

~ add support for rpm building

~ fix link targets not to link anything if there's no object files.

- force param to plugins. useful in local plugins.

- fix plugins loader to properly support local plugins

- support for moved files in darcs
