Mega-commit with improvements and changes done in the past days.

- Introduce package states: unpacked, broken, installed, etc.
  Not yet finished, only unpacked and installed are used for now.

- Move package metadata files in binary packages directly to
  the top directory, this speeds up some ops and makes easier to
  continue working in future changes.

- xbps-bin: -C flag to check the hash of package files has been
  superseded by the 'check' target, which verifies the integrity
  of an installed package.

- Use the 'essential' object when upgrading packages, overwritting
  current files. This is needed for critical packages like sh, libc
  and others.

- Miscellaneous tweaks and improvements thorough the code.

--HG--
extra : convert_revision : 2073fcc123efc24b3e9327b5e22aa91752f20df6

bin/xbps-pkgdb/main.c

@@ -139,7 +139,12 @@ main(int argc, char **argv)
 		prop_dictionary_set_cstring_nocopy(dict, "version", argv[2]);
 		prop_dictionary_set_cstring_nocopy(dict, "short_desc", argv[3]);
 
-		rv = xbps_register_pkg(dict, false, automatic);
+		rv = xbps_set_pkg_state_installed(argv[1],
+		    XBPS_PKG_STATE_INSTALLED);
+		if (rv != 0)
+			exit(EXIT_FAILURE);
+
+		rv = xbps_register_pkg(dict, automatic);
 		if (rv == EEXIST) {
 			printf("%s=> %s-%s already registered.\n",
 			    in_chroot ? "[chroot] " : "", argv[1], argv[2]);