`std.freadall` encounters a premature EOF error when reading files without "b" flag.

[skejeton]

`std.freadall` encounters a premature EOF error when reading files without "b" flag.

[vtereshkov]

It was supposed to be used with "rb" only.

Not even sure about the behavior of C's fread() with "r".

[skejeton]

It should probably throw an appropriate error if it's only intended to work with "rb"

[vtereshkov]

I see freadall() doesn't crash but just returns the .eof error. I think this is acceptable, except that I should have mentioned the "rb" mode requirement in the docs. The docs are now fixed.