Unicode characters in .dx files supported on Mac, not on Linux

[harryaskham]

Discovered trying to move a file with the word "Schrödinger" in a comment from MacOS to Debian :)

On MacOS everything works as expected, umlaut appears in Web view

On Linux

Error:
examples/unicode.dx: hGetContents: invalid argument (invalid byte sequence)

Removing the umlaut fixes things on Linux.

[apaszke]

Yeah we're very unprincipled when it comes to unicode handling. We should take a pass over the whole compiler and be more careful about it.