fix display of whitespace-containing entity-names

As entities can contain underscores/whitespace, we should be
able to display this sentences correctly, for example this
OWL-Sentence:
  XML:
```
  <SubClassOf>
    <Class IRI="#Glass_Walkers"/>
    <Class IRI="#Tribe"/>
  </SubClassOf>
```
  Manchester:
```
  Class: Glass_Walkers SubClassOf: Tribe
```
Should be displayed like this:
`Class: Glass Walkers SubClassOf: Tribe`
and not like this:
`Class: SubClassOf: Tribe`
This occured because Class: `<Glass Walkers>`
could not be correctly replaced (because it was expected to not
contain whitespace). This change now only expects that a
`<>` construct does not contain any more `>` chars.