Windows line endings not working

Hi again,

when opening a file with windows line endings `\r\n`, and renaming a sequence, the file after unmounting is broken.

Starting with

```
>a
GCAC-GTG-T
>b
C-T--AACCC
>c
AT-AACGTAG
```

and renaming one of the sequences gives me

```
>a

GCAC-GTG-T>x.seq
b
C-T--AAC>c

>c
AT-AAC
```

which does not seem right.

Best
Lucas