gst/videofilter/: Port gamma filter to 0.10. Fixes #412704.

gst/videofilter/: Port gamma filter to 0.10. Fixes #412704.

Original commit message from CVS:
Patch by: Mark Nauwelaerts <manauw at skynet be>
* gst/videofilter/Makefile.am:
* gst/videofilter/gstgamma.c: (gst_gamma_base_init),
(gst_gamma_class_init), (gst_gamma_init), (gst_gamma_set_property),
(gst_gamma_get_property), (gst_gamma_calculate_tables),
(oil_tablelookup_u8), (gst_gamma_set_caps),
(gst_gamma_planar411_ip), (gst_gamma_transform_ip), (plugin_init):
Port gamma filter to 0.10. Fixes #412704.
* tests/check/Makefile.am:
* tests/check/elements/videofilter.c: (setup_filter),
(cleanup_filter), (check_filter), (GST_START_TEST),
(videobalance_suite), (videoflip_suite), (gamma_suite), (main):
Add unit tests for videofilters.