Some final fixes for the v4lsrc elements. remove software sync thread (use GST_ELEMENT_THREAD_SUGGESTED instead) make...

Original commit message from CVS:
Some final fixes for the v4lsrc elements.

* remove software sync thread (use GST_ELEMENT_THREAD_SUGGESTED instead)
* make all src elements threadsafe
* fix num_buffer argument setting in v4l2src (VIDIOC_S_PARM)
* re-add bufsize (RO) for v4lmjpegsrc
* fix the A/V sync calculation in all elements (spvf=GST_SECOND/fps, not GST_SECOND*fps)
* probably some more crap....

With all this, it actually works quite well. The TODO files describes the
next steps in order to make a full-featured video recorder based on these
elements and GStreamer (bottom). Making a simple recorder should be fairly
easy now, btw.