Convert elements to use fractions for their framerate.

Convert elements to use fractions for their framerate.

Original commit message from CVS:
* ext/libvisual/visual.c: (gst_visual_src_setcaps), (get_buffer),
(gst_visual_chain):
* ext/ogg/gstogmparse.c: (gst_ogm_parse_chain):
* ext/theora/theoradec.c: (theora_handle_type_packet):
* ext/theora/theoraenc.c: (theora_enc_sink_setcaps),
(theora_enc_chain):
* gst-libs/gst/riff/riff-media.c: (gst_riff_create_video_caps):
* gst-libs/gst/video/video.c: (gst_video_frame_rate):
* gst-libs/gst/video/video.h:
* gst/ffmpegcolorspace/avcodec.h:
* gst/ffmpegcolorspace/gstffmpegcodecmap.c:
(gst_ffmpeg_caps_to_pixfmt):
* gst/ffmpegcolorspace/gstffmpegcolorspace.c:
(gst_ffmpegcsp_set_caps):
* gst/videorate/gstvideorate.c: (gst_videorate_transformcaps),
(gst_videorate_setcaps), (gst_videorate_blank_data),
(gst_videorate_chain):
* gst/videotestsrc/gstvideotestsrc.c:
(gst_videotestsrc_src_fixate), (gst_videotestsrc_getcaps),
(gst_videotestsrc_parse_caps), (gst_videotestsrc_setcaps),
(gst_videotestsrc_event), (gst_videotestsrc_create):
* gst/videotestsrc/gstvideotestsrc.h:
* sys/ximage/ximagesink.c: (gst_ximagesink_xcontext_get),
(gst_ximagesink_setcaps), (gst_ximagesink_change_state),
(gst_ximagesink_get_times), (gst_ximagesink_init):
* sys/ximage/ximagesink.h:
* sys/xvimage/xvimagesink.c: (gst_xvimagesink_get_xv_support),
(gst_xvimagesink_setcaps), (gst_xvimagesink_change_state),
(gst_xvimagesink_get_times), (gst_xvimagesink_init):
* sys/xvimage/xvimagesink.h:
Convert elements to use fractions for their framerate.
V4L elements to come later tonight.