New configuration scheme changes, round 1.

- Configuration file 'xbps-conf.plist' has been splitted off into
  two files: conf.plist and repositories.plist. By default they
  are stored in etc/xbps.
- Changed some members in xbps_handle struct, mostly to make it easy
  to change its value in {cache,root}dir and conffile.
- Made xbps_init() release proplib objects as soon as we don't need
  them, that way it uses 35% less of memory or in some cases even more.

There will be another commit that will implement to read new virtualpkg
settings by the user, as specified in:

	http://code.google.com/p/xbps/issues/detail?id=12

etc/repositories.plist

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<array>
+	<!-- You can specify here your list of repositories,
+	     the first repository that contains a package will
+	     be used for most targets in xbps-bin(8) and
+	     xbps-repo(8), with the exception for updating
+	     on which all repositories will be looked at and
+	     the newest version will be choosen.
+
+	     Optionally a non default HTTP port can also be
+	     specified like that:
+
+		http://foo.local:8080/xbps-repo
+
+	     The order matters, and the top-most matching a package
+	     pattern or name will be used.
+
+	     By default we use the official "public" repositories.
+	     you can add your own local repositories by specifying
+	     the path to the directory. -->
+	<string>http://xbps.nopcode.org/repos/current</string>
+</array>
+</plist>