Add help files for Octave, now Octave shows its documentation

documentation/CMakeLists.txt

 add_subdirectory(Maxima)
+add_subdirectory(Octave)

documentation/Octave/CMakeLists.txt

+install(DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR} DESTINATION ${DATA_INSTALL_DIR}/${PROJECT_NAME}/documentation PATTERN "CMakeLists.txt" EXCLUDE)

src/cantor_part.cpp

@@ -360,7 +360,7 @@ CantorPart::CantorPart( QWidget *parentWidget, QObject *parent, const QVariantLi
     connect(m_showBackendHelp, &QAction::triggered, this, &CantorPart::showBackendHelp);
 
     // Do not display "Show Backend Help" action for Maxima, since we are showing it's integrated documentation
-    if(backend->name() == QLatin1String("Maxima"))
+    if(backend->name() == QLatin1String("Maxima") || backend->name() == QLatin1String("Octave"))
         m_showBackendHelp->setVisible(false);
 
     // Disabled, because uploading to kde store from program don't work

src/panelplugins/documentationpanel/documentationpanelwidget.cpp

@@ -51,6 +51,7 @@ DocumentationPanelWidget::DocumentationPanelWidget(Cantor::Session* session, QWi
     if(!m_engine->setupData())
     {
         qWarning() << "Couldn't setup QtHelp Engine";
+        qWarning() << m_engine->error();
         delete m_engine;
         delete m_textBrowser;
         delete m_tabWidget;