Move av_get_token() from libavfilter to libavutil.

Originally committed as revision 25225 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavfilter/parseutils.h

@@ -27,21 +27,6 @@
 
 #include "libavutil/opt.h"
 
-/**
- * Unescape the given string until a non escaped terminating char,
- * and return the token corresponding to the unescaped string.
- *
- * The normal \ and ' escaping is supported. Leading and trailing
- * whitespaces are removed.
- *
- * @param buf the buffer to parse, buf will be updated to point to the
- * terminating char
- * @param term a 0-terminated list of terminating chars
- * @return the malloced unescaped string, which must be av_freed by
- * the user, NULL in case of allocation failure
- */
-char *av_get_token(const char **buf, const char *term);
-
 /**
  * Put the RGBA values that correspond to color_string in rgba_color.
  *