vpx[dec|enc]: Extract IVF support from the apps.

- Move IVF reading support into ivfdec.c and ivfdec.h
- Move IVF writing support into ivfenc.c and ivfenc.h
- Removed IVF writing code from the SVC example in favor of ivfenc.

Change-Id: I70adf6240d0320fdd232d8546ed573f0f68dd793

ivfenc.h

@@ -0,0 +1,33 @@
+/*
+ *  Copyright (c) 2013 The WebM project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+#ifndef IVFENC_H_
+#define IVFENC_H_
+
+#include "./tools_common.h"
+
+struct vpx_codec_enc_cfg;
+struct vpx_codec_cx_pkt;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void ivf_write_file_header(FILE *outfile,
+                           const struct vpx_codec_enc_cfg *cfg,
+                           uint32_t fourcc,
+                           int frame_cnt);
+void ivf_write_frame_header(FILE *outfile, const struct vpx_codec_cx_pkt *pkt);
+void ivf_write_frame_size(FILE *outfile, size_t size);
+
+#ifdef __cplusplus
+}  /* extern "C" */
+#endif
+
+#endif  /* IVFENC_H_ */