Build system enhancements.

	- Uninstallations now possible.
	- Symlinks from various alternative filenames for library files.
	  (will fail if versions are not of the x.y.z form, though)
	- The quality of the build system’s code has been somewhat
	  lowered during the previous commits. Things will probably have
	  to be done about that in the near(?) future.
Various updates.

	- TODO updated.
	- Several minor fixes to make the use of the recipe more
	  flexible.
	- Packages directory added to the Configuration structure.