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.
Merge pull request #774 from ontohub/fix_display_of_sentences

fix display of whitespace-containing entity-names