gst/net/: Use the timepacket stuff in the provider, include it from gstnet.h, and...

gst/net/: Use the timepacket stuff in the provider, include it from gstnet.h, and add it to the build.

Original commit message from CVS:
2005-11-16  Andy Wingo  <wingo@pobox.com>

* gst/net/Makefile.am:
* gst/net/gstnet.h:
* gst/net/gstnettimeprovider.c:
* gst/net/gstnettimeprovider.h: Use the timepacket stuff in the
provider, include it from gstnet.h, and add it to the build.

* gst/net/gstnettimepacket.h:
* gst/net/gstnettimepacket.c: New files, abstracts out the packet
sending and receiving.