Add the ASS sub document and the ASS tree

Also add views for the ASS tree in read only mode for now

src/Lib/Ass/AssFactory.cc

@@ -15,7+15,7 @@
 
     while (!in.atEnd()) {
         const QString line = in.readLine().trimmed();
 
         // Dectect comment
         if (line.startsWith(";") || line.isEmpty()) {
             lineIndex++;
@@ -63,7+63,7 @@
         for (const auto &styleLine : stylesContent)
             assStyles.push_back(std::make_shared<Style>(styleLine));
         for (const auto &assLine : eventsContent)
-            assLines.push_back(std::make_shared<Line>(assLine));
+            assLines.push_back(std::make_shared<Line>(this, assLine));
     } catch (const std::runtime_error &e) {
         qCritical() << "Failed to create ASS style or events with error:" << e.what();
     }
@@ -138,3 +138,13 @@ AssFactory::getInfoSection() const noexcept
 {
     return assInfo;
 }
+
+bool
+AssFactory::hasStyle(const QString &name) const noexcept
+{
+    for (const auto &stylePtr : assStyles) {
+        if (stylePtr->getElementName() == name)
+            return true;
+    }
+    return false;
+}