Adds new converters

Adds a MKV to HEVC converter which aims to reduce file-sizes
Adds a MKV to MP4 transcoder which allows selection of each type of stream

src/main/java/net/knarcraft/ffmpegconverter/streams/SubtitleStream.java

@@ -103,7 +103,9 @@ public class SubtitleStream extends AbstractStream implements StreamObject {
         return !titleLowercase.matches(".*si(ng|gn)s?[ &/a-z]+songs?.*") &&
                 !titleLowercase.matches(".*songs?[ &/a-z]+si(gn|ng)s?.*") &&
                 !titleLowercase.matches(".*forced.*") &&
-                !titleLowercase.matches(".*s&s.*");
+                !titleLowercase.matches(".*s&s.*") &&
+                !titleLowercase.matches("signs?") &&
+                !titleLowercase.matches("songs?");
     }
 
 }