Player breaks https

[kylepolich]

To reproduce:

• Go to site.
• Play current episode (Winograd Schema Challenge)
• Notice https goes to http because the image is the wrong protocol.

To fix it, the player needs to check the link and force it to https if it is http.

[hlib-lozhkovyi]

We have the same http=>https logic for cached episodes. Now we are moving to the lambda's backend and need to be careful with that cases.

I expect could happen for blogs.

However, this PR #701 fix that logic for episodes page and player in all cases.

[hlib-lozhkovyi]

Note that I have created the PR for master to fix critical issue in the player ASAP.