gst/base/gstbasesrc.c: Move some stuff around and cleanup things.

gst/base/gstbasesrc.c: Move some stuff around and cleanup things.

Original commit message from CVS:
* gst/base/gstbasesrc.c: (gst_base_src_class_init),
(gst_base_src_init), (gst_base_src_query),
(gst_base_src_default_newsegment),
(gst_base_src_configure_segment), (gst_base_src_do_seek),
(gst_base_src_send_event), (gst_base_src_event_handler),
(gst_base_src_pad_get_range), (gst_base_src_loop),
(gst_base_src_unlock), (gst_base_src_default_negotiate),
(gst_base_src_start), (gst_base_src_deactivate),
(gst_base_src_activate_push), (gst_base_src_change_state):
Move some stuff around and cleanup things.