lt-tmxproc doesn't keep escaped input chars escaped in output

```
$ echo "3 > 2" | apertium -f txt -d . nob-nno
3 > 2

$ echo "1 > 2" | apertium -f txt -d . -m word.tmx -o nob-nno nob-nno
Error: Malformed input stream.

$ echo "how about 1 < 2 then?" | apertium -f txt -d . -m word.tmx -o nob-nno nob-nno
*how *about 1

# possible workarounds:
$ echo "1 < 2" | apertium -f html -d . -m word.tmx -o nob-nno nob-nno
1 < 2

$ echo "1 < 2" | apertium -f html-noent -d . -m word.tmx -o nob-nno nob-nno
1 < 2

$ echo "1 < 2" | apertium -f html-alt -d . -m word.tmx -o nob-nno nob-nno
1 < 2

```

word.tmx is irrelevant:
```xml

foo


bar

```