GfDeclaration now implements OWLSentence

Also:

  - improved GfReportExporter
  - HTML escaping in Details-view
Improve GF Report Exporter

Simplified the analysis of ambiguity at various levels (tree, ACE, OWL).
Fix in GF Report Exporter
GF: Preliminary support for question answering

Extract GfQuestion from GfDeclaration.
Present answers as lists of function names.
TODO:

  - answers should be presented as words in lemma form in the current language
  - answers should be filtered (e.g. to remove owl:Thing)
  - question detection should not rely on the presence of question mark in a non-ACE input
  - general cleanup
Add OWLFunctionalSyntaxExporter

Use OWL exporters with GF wikis
Improve question answering
Improve GF report generation

Add statistics on tree size and OWL signature size
GF: answers are now multilingual
Improve locale handling
Merge branch 'master' into gf_with_owl
Add missing dots in strings.
Ambiguous entries are now also mapped to OWL

Currently only the first reading is integrated into the
knowledge base.
TODO: integrate the disjunction of all the readings
Include questions in the GF report
Update questions after grammar recompile
Exclude grammar modules from GF report
Merge branch 'master' into gf_with_owl
Some cleanup of OWL support

Currently only for GF-based wikis
More OWL-related cleanup
Merge branch 'master' into gf_with_owl
Merge branch 'master' into gf_with_owl