FLUID-4844: Update Captionator and change our use of 'mode' to be spec compliant.
FLUID-4844: Modifying the way we set 'mode' so that captions work in Safari.
Merge remote-tracking branch 'michelle/FLUID-4844-b'

* michelle/FLUID-4844-b:
  FLUID-4844: Modifying the way we set 'mode' so that captions work in Safari.
  FLUID-4844: Update Captionator and change our use of 'mode' to be spec compliant.
Merge branch 'master' into FLUID-4824