logic: reimplemented task system to abort ast visiting

* reimplemented interrupting TaskParseCxx by adding a listener for the MessageInterruptTask and returning a failure status code on update. This cancels the parent sequence task which results in the indexed items not getting inserted into the persistent storage
* removed the capability for interrupting from TaskScheduler
* changed task system to be closer to the standard behavior tree implementation
* changed task system to accommodate the 3 status return types: Running, Success and Failure
* made TaskGroupSequential fail once a member task fails
* made TaskGroupParallel fail once a member task fails
* split TaskParse... into one task for indexing and one task for injecting
* added TaskRunner that handles updating and resetting the managed task
* fixed numbers that are shown as parsed file count in indexing ui
* fixed deadlock that originated from interaction between TaskScheduler and MessageQueue (one thread wanted to destroy a message listener on a task while the other one wanted to send as message as a task)

src/lib/utility/scheduling/TaskRunner.cpp

@@ -0,0 +1,34 @@
+#include "utility/scheduling/TaskRunner.h"
+
+TaskRunner::TaskRunner(std::shared_ptr<Task> task)
+	: m_task(task)
+	, m_reset(false)
+{
+}
+
+TaskRunner::~TaskRunner()
+{
+}
+
+//Task::TaskState TaskRunner::getState() const
+//{
+//	return m_task->getState();
+//}
+
+Task::TaskState TaskRunner::update()
+{
+	if (m_reset)
+	{
+		m_task->reset();
+		m_reset = false;
+	}
+
+	return m_task->update();
+}
+
+void TaskRunner::reset()
+{
+	m_reset = true;
+}
+
+