Added videosignal plugin with two plugins to analyse video frames.

Added videosignal plugin with two plugins to analyse video frames.

Original commit message from CVS:
* configure.ac:
* docs/plugins/Makefile.am:
* docs/plugins/gst-plugins-bad-plugins-docs.sgml:
* docs/plugins/gst-plugins-bad-plugins-sections.txt:
* docs/plugins/inspect/plugin-videosignal.xml:
* gst/videosignal/Makefile.am:
* gst/videosignal/gstvideoanalyse.c: (gst_video_analyse_set_caps),
(gst_video_analyse_post_message), (gst_video_analyse_420),
(gst_video_analyse_transform_ip), (gst_video_analyse_set_property),
(gst_video_analyse_get_property), (gst_video_analyse_base_init),
(gst_video_analyse_class_init), (gst_video_analyse_init),
(gst_video_analyse_get_type):
* gst/videosignal/gstvideoanalyse.h:
* gst/videosignal/gstvideodetect.c: (gst_video_detect_set_caps),
(gst_video_detect_post_message),
(gst_video_detect_calc_brightness), (gst_video_detect_420),
(gst_video_detect_transform_ip), (gst_video_detect_set_property),
(gst_video_detect_get_property), (gst_video_detect_base_init),
(gst_video_detect_class_init), (gst_video_detect_init),
(gst_video_detect_get_type):
* gst/videosignal/gstvideodetect.h:
* gst/videosignal/gstvideosignal.c: (plugin_init):
* gst/videosignal/gstvideosignal.h:
Added videosignal plugin with two plugins to analyse video frames.
Added videoanalyse to report about brightness and variance in video
frames.
Added videodetect to detect predefined patterns in a video signal.