Totally rewritten registry handling.

Totally rewritten registry handling.

Original commit message from CVS:
Totally rewritten registry handling.
- move the registry save/load code into a gstregistry subclass, this
will make it possible to use other registries (flat file, web based,
RDBMS type, etc..)
- a simple GMarkup xml registry is implemented
- use standard statically linked plugins for core elements.
- GstPlugin has a very well defined set of functions now
A little bytestream hack..
Added more info to -inspect.
Some more debugging info for clocking.
Small cleanups

I use ./gst-register --gst-plugin-path=/opt/src/sourceforge/gst-plugins/gst-libs:/opt/src/sourceforge/gst-plugins/
to register core and gst-plugins now.