Adds CastUtils special cases for Uint8Array
Adds CastUtils special cases for Uint8Array

Using JSON.stringify and JSON.parse turns Uint8Arrays into generic
objects, but we need them to be actually be Uint8Arrays.
This adds a special case to CastUtil.serialize and CastUtils.deserialize
to preserve the object type of Uint8Arrays.

Closes #1716

Change-Id: I370711c016c5d5ba21cdbccb3d970c6e074a3edd

shaka-project/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,tvoli/shaka-player,tvoli/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player