Since commit 45ca8876b2f5267f7edb842b6d56d7a6c271ccb3 nobody is using gst_opencv_get_ipl_depth_and_channels() or gst_opencv_parse_iplimage_params_from_structure(). Remove this dead code.
Switch remaining C files to C++ for consistency with other OpeCV elements, and support of the new 2.4.11 API. https://bugzilla.gnome.org/show_bug.cgi?id=754148