SDK / exoplayer

- The fmp4 extractor was reading from sampleEncryptionData even
  for not-encrypted samples, which I'm pretty sure isn't right.
  Fixed this. For all encrypted content I've seen, this change
  will be a no-op because isEncrypted is always true if there's
  an encryptionBox present.
- Made webm extractor only set cryptoInfo if isEncrypted is true.
- Align variable naming in the two extractors, for clarity.

- Rather than returning a map, return a DrmInitData object,
  with mapped and non-mapped implementations.
- Include a suitable mimeType to pass to the MediaDrm. Previously
  we were incorrectly passing the mimeType of the samples,
  where-as MediaDrm expects the container mimeType. Note that
  it doesn't matter whether the mimeType starts with "video" or
  "audio", hence using video mimeTypes everywhere.

Not yet used by anything.

Issue: #151

- Correctly handle bandwidth NO_ESTIMATE case.
- Don't consider switching without a previous chunk.

Set the duration on the MediaFormat instead.

Issue: #327

It was possible for a codec input buffer to be filled with two frames' worth of
data, if seekTo was called after populating a buffer, if waitingForKeys was true
and seeking did not trigger a flush. This caused the CryptoInfo to be configured
as if the input buffer contained a large amount of reconfiguration data as
cleartext.

Move resetting waitingForKeys to flushCodec, so that we don't try to read the
next sample from the source until the first one has been consumed or discarded.

Also remove uriIsFullStream. It's not doing anything particularly
useful, so I think it makes sense to remove it from the public API;
it's unlikely anyone is using it.

Issue: #329

It seems fairly safe to assume a playlist wont be blacklisted
within 1ms of the device booting :).

Add support for GEOB and PRIV ID3 frames.

Mime type string always finish with a single 0 byte

- Fixed issue in the calculation of size of objectData
- Indentation fixes

Removed the unused method indexOfNot

Modified parse method to take into account different lengths for the
termination character (1 for UTF-8 and ISO-8859-1; 2 for UTF-16 and
UTF-16BE).

For fields encoded using UTF-16 or UTF-16BE charsets when looking for
termination character we have to look for two zero consecutive bytes.

Otherwise, as many characters encoded with UTF-16 or UTF-16BE has one
of their 2 bytes set with the value zero, we will be truncating text
fields.

- Added support for ID3 frames of types GEOB and PRIV.

 - GEOB type is commonly used by dynamic ads provider to include in the
stream information about the ads to be played.
 - PRIV type is commonly used for time synchronization (example:
synchronizing playback of a live stream and its webvtt captions) and
also by analytics companies to include tracking information in the
stream.

- Added a sample stream from Apple that contains ID3 metadata.

Better management of blacklisted playlists

Note: I'm fairly confident that NetworkLoadable.Parser implementations
can live without the inputEncoding being specified. But not completely
100%...

Issue: #311
Issue: #56

The return value here assumed that the time being searched for
was beyond the start time of the last segment. This fix also
handles the case where the time is prior to the start of the
first segment.

The only downside of this change is that MediaPresentationDescriptionParser
is no longer stateless.

This issue didn't have any material impact on playbacks, but
fixing it anyway to be technically correct.

1. Clear prefixFlags when a NAL unit is found.
2. continueBuffering should return true if loading is finished.

Calling clearStaleBlacklistedPlaylist within getNextVariantIndex method.

Clear stale blacklist in getChunkOperation before getting next variant.
This ensures:
1.- Player resilience to failures, always trying to look for a working
playlist that allows player to non stop playback.
2.- High quality blacklisted playlists can be reused in case they go up
after a failure. Player always trying to provide the best user
experience.

- Method evaluatePlayListBlackListedTimestamps renamed to
clearStaleBlacklistedPlaylists
- Code formatted to be consistent with style elsewhere.

Added an expiration time field to playlists blacklisted to allow
Exoplayer to continue playback when playlists that failed were
recovered from a bad state.

In live environments, some times occur that primary encoder stop
working for a while. In that cases, HLS failover mechanism in the
player should detect the situation and “switch” to playlists served by
the backup encoder (in case a backup encoder exists). This was well
managed before these changes.

However, and to ensure a playback experience that can recover itself
from temporary issues, we cannot blacklist a playlist forever. When
streaming live events using HLS, it is quite typical that the player
needs to switch from primary to backup playlists, and from backup to
primary ones, from time to time to have playback working when temporary
issues in the network/encoder are happening. Most of the issues are
recoverable, so what I have implemented is a mechanism that makes
blacklisted playlist to be available again after a while (60 seconds).

Evaluation of this algorithm should happen just when something fails.
If player is working with a backup playlist, it shouldn’t switch to the
primary one at least something fail.

Support is provided for the following schemes:

urn:mpeg:dash:utc:direct:2012
urn:mpeg:dash:utc:http-iso:2014
urn:mpeg:dash:utc:http-xsdate:2012
urn:mpeg:dash:utc:http-xsdate:2014

- Data needs to be unescaped before it's passed to SeiReader.
- SeiReader should loop over potentially multiple child messages.
- I also changed the sample passed to the EIA-608 renderer so that
  it's the entire sei message payload. The first 8 bytes are
  unnecessary, but it seems nicer conceptually to do it this way.

Issue: #295