added plugin_desc structures to libs, which makes their locations cached in the registry. this speeds plugin loading ...

Original commit message from CVS:
* added plugin_desc structures to libs, which makes their locations cached in the registry. this
speeds plugin loading considerably, especially on uninstalled versions.

* put the lib path before all others, for speed reasons.

* some fixes to adder's caps.

* added linefeeds (\n) to GST_DEBUG strings to match GST_INFO behavior. this is more sane. all
code will need to be converted. i think some perl can do this.