Standardize use of header files, making internal.h primary.

Standardize use of header files, making internal.h primary.
	* qemud/internal.h, qemud/qemud.h: Rename this file so it
	doesn't conflict with src/internal.h.
	* HACKING: Document how header files should be used.
	* qemud/Makefile.am: Add src/ directory to includes.
	* qemud/event.c, qemud/mdns.c, qemud/qemud.c, qemud/remote.c,
	qemud/remote_protocol.c, qemud/remote_protocol.h,
	qemud/remote_protocol.x, src/buf.c, src/libvirt.c,
	src/nodeinfo.c, src/qemu_conf.c, src/qemu_driver.c,
	src/stats_linux.c, src/storage_backend.c, src/storage_backend_fs.c,
	src/storage_backend_iscsi.c, src/storage_backend_logical.c,
	src/storage_conf.c, src/storage_driver.c, src/util.c,
	src/util.h, src/virsh.c, src/virterror.c, src/xend_internal.c,
	src/xml.c, tests/reconnect.c, tests/xmlrpctest.c,
	tests/qparamtest.c: Standardize	use of header files.
	* docs/*, po/*: Rebuild docs.