Refactored *_new() functions.

Refactored *_new() functions.

Original commit message from CVS:
* docs/gst/gstreamer-sections.txt:
* gst/gstghostpad.c: (gst_proxy_pad_do_getcaps),
(gst_proxy_pad_do_setcaps), (gst_proxy_pad_set_target_unlocked),
(gst_proxy_pad_dispose), (gst_ghost_pad_new_full),
(gst_ghost_pad_new_no_target), (gst_ghost_pad_new),
(gst_ghost_pad_new_from_template),
(gst_ghost_pad_new_no_target_from_template):
* gst/gstghostpad.h:
Refactored *_new() functions.
Templates are now used as a g_object_new() parameter.
Use template in _do_getcaps() if we don't have a target.
Small documentation cleanups.
Added two new constructors:
gst_ghost_pad_new_from_template()
gst_ghost_pad_new_no_target_from_template()
* tests/check/gst/gstghostpad.c: (GST_START_TEST),
(gst_ghost_pad_suite):
Added tests for new ghostpad instanciation functions.
API additions: gst_ghost_pad_new_from_template,
gst_ghost_pad_new_no_target_from_template