Changed ifstream open mode to binary for overmap and player JSON.

[DanmakuDan]

Fixes #12945. I'm guessing you can't have a Windows file with long lines and \r\n and expect Windows to know where your stream pointer is. I think the 4 MB stream location where it fails is probably more than a coincidence, but sample programs can break the pointer with only a few bytes.

[kevingranade]

My only concern is breaking existing saves, however json.cpp might handle it transparently, which would be nice.

[DanmakuDan]

I think the main difference on the Windows side is how binary/text mode deals with control characters. The JSON code already looks like it deals with them without depending on the input mode by parsing each byte.

[kevingranade]

Pulling to build, I can't test, but it's the right thing to do anyway so I'll go ahead ad pull it as long as it doesn't seem to break anything.

[karlnp]

I tested it on mingw64/win7, it works fine.

[kevingranade]

Thanks for the confirmation :)

[chaosvolt]

Ooh, I was about to wonder whether this actually did anything, but this was just now merged. Will be eager to see the results.

EDIT: Confirmed, build 3426 seems to be working fine to me. Thank you to DanmakuDan for this.

[kevingranade]

Fixed #12945