obs-x264: Log ignored options

When an x264 option doesn't include a "=", it is silently ignored. This
is frustrating for users. Log when part of the options string is
ignored.

Aside from logging, this commit should not change behavior.

plugins/obs-x264/obs-x264-options.h

@@ -10,6 +10,8 @@ struct obs_x264_option {
 struct obs_x264_options {
 	size_t count;
 	struct obs_x264_option *options;
+	size_t ignored_word_count;
+	char **ignored_words;
 	char **input_words;
 };