Revert string transcode changes

[musm]

add a test and trim leading whitespace

[yuyichao]

LGTM.

FWIW, I don't see why the original change was needed.

[yuyichao]

Missing new line.

[musm]

why prefer a newline?

[musm]

ok fixed. mind merging this one?

[simonster]

I'm not sure this is actually right. It seems to round trip, but I think that's just because we aren't converting properly on either end. If you put UTF-8 into MATLAB you will get UTF-8 out, but MATLAB's internal encoding appears to be UCS-2. Compare:

julia> str = "λ";

julia> mat"$str(1)+0"
206.0

which is UTF-8 vs. entering the same thing into MATLAB directly:

>> x = 'λ';
>> x(1)+0

ans =

   955

which is the actual Unicode codepoint.

[musm]

Interesting, I see the same problem on both on this commit and on master

[simonster]

The transcode change should have fixed how strings come out of MATLAB, but it didn't fix how we put strings into MATLAB, so that makes sense.

[simonster]

See #80 for the fix to encode strings properly on construction.