Remove rt deadline.

The "good" speed levels are universally better than the "rt" ones,
running faster to achieve the same quality.

rt mode also turned off alt refs and lag-in-frames, but these
are still accessible separately (and the low latency test case
explicitly sets them).

Some features were used by the rt scale and not the good scale.
Two additional "good" levels, 7 and 8, were added to accomidate
these features and not reduce test coverage.

Change-Id: I3a6a78ddb664511762c197bc41f3a9909665b565

aom/aom_encoder.h

diff --git a/aom/aom_encoder.h b/aom/aom_encoder.h
index e992334..14c9f0c 100644
--- a/aom/aom_encoder.h
+++ b/aom/aom_encoder.h
@@ -695,8 +695,6 @@
  */
 aom_fixed_buf_t *aom_codec_get_global_headers(aom_codec_ctx_t *ctx);
 
-/*!\brief deadline parameter analogous to AVx REALTIME mode. */
-#define AOM_DL_REALTIME (1)
 /*!\brief deadline parameter analogous to  AVx GOOD QUALITY mode. */
 #define AOM_DL_GOOD_QUALITY (1000000)
 /*!\brief Encode a frame
@@ -712,7 +710,7 @@
  * best possible frame by specifying a deadline of '0'. This deadline
  * supercedes the AVx notion of "best quality, good quality, realtime".
  * Applications that wish to map these former settings to the new deadline
- * based system can use the symbols #AOM_DL_REALTIME and #AOM_DL_GOOD_QUALITY.
+ * based system can use the symbol #AOM_DL_GOOD_QUALITY.
  *
  * When the last frame has been passed to the encoder, this function should
  * continue to be called, with the img parameter set to NULL. This will