implemented core subtitle support

app/codec/exportcodec.h

@@ -25,6 +25,7 @@
 #include <QString>
 
 #include "common/define.h"
+#include "render/subtitleparams.h"
 
 namespace olive {
 
@@ -52,6 +53,9 @@ public:
     kCodecVorbis,
     kCodecFLAC,
 
+    // Subtitle codecs
+    kCodecSRT,
+
     kCodecCount
   };
 
@@ -59,6 +63,8 @@ public:
 
   static bool IsCodecAStillImage(Codec c);
 
+  static SubtitleParams::Encoding GetDefaultSubtitleEncoding(Codec c);
+
 };
 
 }