It is possible to have two abbr two ex in the same expan

Looking at https://github.com/lascivaroma/cil004-00000/blob/master/data/cil004-00000/00002/cil004-00000.00002.manfred-lat1.xml

```xml
<expan><abbr>d</abbr><ex>uum</ex><abbr>v</abbr></expan><expan><ex>irum</ex></expan>
```
should be
```xml
<expan><abbr>d</abbr><ex>uum</ex><abbr>v</abbr><ex>irum</ex></expan>
```