Fix SmoothStreamingManifest to handle large timestamps.
Correctly handle zero length fragmentRun.
Clean up TTML timestamp parsing.
Fix StreamingDrmSessionmanager.

Use locally bound variable instead of class variable.
Merge DashLiveMpdFetcher logic into generic ManifestFetcher.

This allows ManifestFetcher to both execute the initial
manifest load and be plugged into an ExoPlayer ChunkSource,
where it can be used for repeated manfiest refreshes during
live playback.
Ignore blockingSendMessage calls after release.

Previously we'd end up blocking forever in this case, which
is the worst thing we could do :). We could either throw an
exception or just print a warning. Printing a warning is more
in line with what other methods do (Handler prints a "sending
message to dead thread" warning).