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/Makefile

@@ -1,6 +1,6 @@
 -include ../config.mk
 
-CONF_FILE =	xbps-conf.plist
+CONF_FILE =	conf.plist repositories.plist
 
 .PHONY: all
 all: