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/CMakeLists.txt

@@ -192,6 +192,10 @@ add_files(
 	data/StorageStats.h
 	data/TaskCleanStorage.cpp
 	data/TaskCleanStorage.h
+	data/TaskInjectStorage.cpp
+	data/TaskInjectStorage.h
+	data/TaskRepeatWhileUnparsedSourceFilesAvailable.cpp
+	data/TaskRepeatWhileUnparsedSourceFilesAvailable.h
 
 	settings/ApplicationSettings.cpp
 	settings/ApplicationSettings.h
@@ -312,6 +316,8 @@ add_files(
 	utility/scheduling/TaskGroupSequential.h
 	utility/scheduling/TaskLambda.cpp
 	utility/scheduling/TaskLambda.h
+	utility/scheduling/TaskRunner.cpp
+	utility/scheduling/TaskRunner.h
 	utility/scheduling/TaskScheduler.cpp
 	utility/scheduling/TaskScheduler.h