Remove GST_DISABLE_(ENUMTYPES|INDEX|URI) everywhere.

Remove GST_DISABLE_(ENUMTYPES|INDEX|URI) everywhere.

Original commit message from CVS:
* configure.ac:
* docs/gst/gstreamer-sections.txt:
* docs/gst/gstreamer.types:
* docs/gst/gstreamer.types.in:
* gst/Makefile.am:
* gst/gst.c:
* gst/gstbin.c: (gst_bin_class_init), (gst_bin_set_index_func):
* gst/gstconfig.h.in:
* gst/gstelement.c: (gst_element_get_index):
* gst/gstregistrybinary.c: (gst_registry_binary_save_feature),
(gst_registry_binary_load_feature),
(gst_registry_binary_read_cache):
* gst/gstregistryxml.c: (load_feature),
(gst_registry_xml_read_cache), (gst_registry_xml_save_feature):
* plugins/Makefile.am:
* tools/gst-indent:
* tools/gst-inspect.c: (print_index_info), (print_element_list),
(print_plugin_features), (print_element_features):
* tools/gst-xmlinspect.c: (print_event_masks),
(print_element_info):
* win32/common/gstconfig.h:
Remove GST_DISABLE_(ENUMTYPES|INDEX|URI) everywhere.
Disabling the indexers and URI handler code will only reduce the
required amount of memory by a very small amount but on the other hand
requires much more maintaince work. Apart from that many places of
code are broken when disabling them.
Disabling the enum types doesn't reduce the required amount of memory
by more than a few bytes and makes it hard to fix bugs like #539772,
i.e. use the enums as GObject properties.