TW-1827: Extract annotations from a task

- Thanks to Ryan.

src/Task.cpp

@@ -1032,6 +1032,17 @@ std::string Task::composeJSON (bool decorate /*= false*/) const
   return out.str ();
 }
 
+////////////////////////////////////////////////////////////////////////////////
+int Task::getAnnotationCount () const
+{
+  int count = 0;
+  for (auto& ann : data)
+    if (! ann.first.compare (0, 11, "annotation_", 11))
+      ++count;
+
+  return count;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 bool Task::hasAnnotations () const
 {