Save session-specific options in pending session data when waiting on media keys

[gesinger]

Instead of always using new options, persist options passed when adding session data to the pendingSessionData array to allow for different options per session created.

This fixes cases where two encrypted pieces of media are in the same manifest, and a user set up the sessions in advance using initializeMediaKeys. Previously, the newest options would be used for all sessions. This provides the relevant options.

Testing

Because this case occurs when the same manifest has content with different keys, finding a source for testing is a bit of a challenge. I was able to combine two clear key encrypted sources into one manifest using https://github.com/gesinger/encrypted-video-creator, and can share the instructions/content, but the general steps are:

1. Run the script using default options on a source two times (with different destinations)
2. Combine the audio/video stream manifests, adding an EXT-X-DISCONTINUITY tag in-between where one media ends and the other begins
3. Combine the sample-code.js files by copying the keys array over as keys2 (or some more appropriate name), and the getLicense function as getLicense2, then initializeMediaKeys separately for each

[alex-barstow]

LGTM