Add support for video subtitles

[asciimo]

A closed captioning icon on the video activity should toggle subtitles for the video.

Ideally, the subtitles should reflect the language of the video. I think the Right Way is to drop in standard subtitle videos that are tuned to the timecode of the videos.

Can subtitles be embedded in the video file? If not, should they be downloaded from a separate URL in the same way the video will be?

[asciimo]

Here are the subtitles for the current 10bl video. Just putting them here so they don't get lost.

We all oppose animal abuse. Many of us care deeply for our family dogs, cats, and other animals.
Cows are gentle and loving. Pigs are smart and playful. Chickens form complex social groups and hens are caring mothers. And even fish enjoy cuddling and can feel pain.
Each is an individual with his or her own interests. Each experiences their own feelings of love, joy, sadness, and fear.
But this is how we treat these very animals when we raise them for food…

Hens are stuffed up to seven birds in small cages unable to spread their wings or turn around. The wire mesh floors and walls cut their feet and tear their feathers. Their beaks are cut off with a hot blade to prevent stress-induced pecking. And, since male chicks don't lay eggs, they are ground alive or suffocated in plastic garbage bags at birth.
Egg-laying hens, once considered "spent," are ground up for cheap feed. And broiler chickens are bred to grow so large that their bodies can't even support their own weight.
Mother cows are impregnated with a metal rod each year to keep their milk flowing, then, so we can drink their milk, their newborns are taken away. Male offspring are confined and malnourished in plastic crates and then killed for veal. The mother cows are subjected to this cycle until their own untimely death; usually within just a few years.
Mother pigs spend most of their lives in tight metal crates. Their babies are torn from them and castrated without anesthesia, tails are violently clipped and, then, the four-month-olds are killed for food. On most farms, unwanted “runts” are killed by “thumping,” or slamming their heads against the floor.
Sea life are caught in nets, suffocated and skinned alive. Three fourths of the world's fisheries are exploited or depleted and we could see fishless oceans by the year 2048. For every one pound of fish caught, up to five pounds are inadvertently caught and discarded, including dolphins, sharks, and other innocent creatures.
Even so-called “humane meat” or “free range” isn’t what it seems when you consider the overall treatment and final moments for these sentient beings. Practices that are labelled “humane” are anything but and are implemented on any size farm. "Cage-free" eggs come from chickens crammed by the thousands into dark warehouses and all of these practices … are legal.

But, we can stop these atrocities … every time we sit down at the table … by switching to cruelty-free, plant-based foods.
By going vegan.
Unlike animal agriculture, plant-based foods pollute the planet far less and help keep our air, streams, rivers, lakes, and oceans more sustainable. Plant-based foods also help to lower your risk of cancer, heart disease and diabetes.
Fortunately each of us has the power to choose healthy alternatives to animal products every time we eat. One person's vegan diet, free of meat, fish, dairy and eggs can prevent the deaths of up to 100 animals per year. This includes more than 30 land animals such as chickens, turkeys, cows, pigs, and dozens more fish and other aquatic animals. Animals who are capable of feeling pain and have complex social groups. A vegan diet aligns our daily choices with our deeply held values. Millions of people have already made this healthy compassionate choice.
And you can find delicious vegan options in your localsupermarket, natural and frozen foods sections, at farmers markets and even online. They’re in your school cafeteria, your favorite fast food restaurant and even in convenience stores. Plus, everything you eat can now be made vegan.
Millions have made the switch.
Do you want to help end the suffering of billions of animals raised for food and pledge to go vegan?
Welcome to a more compassionate world…