Major changes to not depend on cksum and db from NetBSD.

Two new utilities in C have been created:
	- xbps-digest: shows the SHA256 hash for a file.
	- xbps-pkgdb: handles dependency stuff via proplib.

Templates should use now $build_depends and change $checksum to be
a SHA256 hash. That means that I'm currently using xbps on Linux and
I lost interest on NetBSD, perhaps I'll add support for it in the
future.

Only git and its dependencies have been converted, as well as vim.

--HG--
extra : convert_revision : 53a7e030ca6b6d02bb6cd3e51d42b7d5702c1b57

.gitignore

@@ -3,3 +3,4 @@ depot/
 packages/
 srcdistdir/
 builddir/
+utils/