check/gst/gstvalue.c: Added subtract checks.

check/gst/gstvalue.c: Added subtract checks.

Original commit message from CVS:
* check/gst/gstvalue.c: (GST_START_TEST), (gst_value_suite):
Added subtract checks.

* docs/design/part-events.txt:
Some more docs about newsegment

* gst/gstbin.c: (gst_bin_change_state), (bin_bus_handler):
Fix FIXME

* gst/gstcaps.c: (gst_caps_to_string):
Add comments, cleanups.

* gst/gstelement.c: (gst_element_save_thyself):
cleanups

* gst/gstvalue.c: (gst_value_collect_int_range),
(gst_string_unwrap), (gst_value_union_int_int_range),
(gst_value_union_int_range_int_range),
(gst_value_intersect_int_int_range),
(gst_value_intersect_int_range_int_range),
(gst_value_intersect_double_double_range),
(gst_value_intersect_double_range_double_range),
(gst_value_intersect_list), (gst_value_subtract_int_int_range),
(gst_value_subtract_int_range_int),
(gst_value_subtract_double_range_double),
(gst_value_subtract_double_range_double_range),
(gst_value_subtract_from_list), (gst_value_subtract_list),
(gst_value_can_compare), (gst_value_compare_fraction):
Cleanups, add comments, remove unneeded asserts.