Parse scaling list from SPS

This is required for the dimensions to be calcuated properly when
streaming using the high profile (at least for the encoder I'm
using). Without this, the scaling list isn't skipped over and
the parsed dimensions are incorrect.

When the dimensions are incorrect, the MPEG-DASH manifest is
generated incorrectly.
Don't truncate framerate for MPEG-DASH

When pushing 29.97fps RTMP streams, the manifest shows an
incorrect frame rate of "29", not "30000/1001" as it should be.