SDK / exoplayer

- Handle read returning NOTHING_READ for AC-3 streams.
- Remove extra checks for the audio track being initialized.
- Call isInitialized() instead of checking audioTrack != null.

- We can't refer to UnsupportedSchemeException outside of the
V18 compat inner classes.
- There were also a few missing return; calls.

ac3Bitrate is set only after the first buffer is handled, which meant that
getting the playback position would cause a divide by zero before then.

When playing back AC-3 content, the ac3Bitrate will always be set after the
first buffer is handled, so return a 0 position if it is not set.

Also add missing file.

- Adds support for dash manifests that define SegmentTemplate
  but no SegmentTimeline.
- Assumes that the device clock is correct when calculating which
  segments to load. The final step here is to use the Utc timing
  element in the DASH manifest to obtain an accurate client clock.
- Doesn't yet enforce that the client shouldn't load segments that
  are in the future or behind the live window.

This wasn't actually used for anything other than showing a
toast, which is now generated based on the manifest instead.

Also update gradle files.

This fixes the referenced issue, except that the MPD parser
needs to actually parse out UUID and binary data for schemes
that we wish to support. Alternatively, it's easy to applications
to do this themselves by extending the parser and overriding
the parseContentProtection and buildContentProtection methods.

Github Issue: #119

It's cleaner to not inject data into the extractor only
so that it can be read out as though it were parsed from
the stream. This is also an incremental step towards
fixing Github issue #119.

Issue: 186

Issue: 186

Note: This adds support for the majority of DASH live streams,
however we do not yet correctly support live streams that rely
on UtcTimingElements in their manifests.

Issue: #52

Plus start to properly document the SmoothStreaming package.
Note that where the documentation is a little vague, this is
because the original SmoothStreaming documentation is equally
vague!

The timestamp scaling in SegmentBase.getSegmentTimeUs was
overflowing for some streams. Apply a similar trick to that
applied in the SmoothStreaming case to fix it.

gradle plugin 0.14.4 fixes

fixes broken import statements