Add av1C generation.

- Add sequence header parser in av1_config.c to produce av1C.
- Add av1C reader and writer functions.

BUG=aomedia:2027

Change-Id: I42322cd56bf2c2c6a7c18b67c1a7d6296fb9fe61
diff --git a/test/test.cmake b/test/test.cmake
index 32f8116..b16ae14 100644
--- a/test/test.cmake
+++ b/test/test.cmake
@@ -26,6 +26,7 @@
 list(APPEND AOM_UNIT_TEST_COMMON_SOURCES
             "${AOM_ROOT}/test/acm_random.h"
             "${AOM_ROOT}/test/aom_integer_test.cc"
+            "${AOM_ROOT}/test/av1_config_test.cc"
             "${AOM_ROOT}/test/blockd_test.cc"
             "${AOM_ROOT}/test/clear_system_state.h"
             "${AOM_ROOT}/test/codec_factory.h"