add argument singlejob to TaskScheduler

README.md

@@ -49,7 +49,7 @@ The basic idea is to instantiate one or multiple schedulers and map specific ino
 pyinotifyd has different schedulers to schedule tasks with an optional delay. The advantages of using a scheduler are consistent logging and the possibility to cancel delayed tasks. Furthermore, schedulers have the ability to differentiate between files and directories.
 
 ### TaskScheduler
-Schedule a custom python method *job* with an optional *delay* in seconds. Skip scheduling of tasks for files and/or directories according to *files* and *dirs* arguments. If there already is a scheduled task, re-schedule it with *delay*. Use *logname* in log messages. All additional modules, functions and variables that are defined in the config file and are needed within the *job*, need to be passed as dictionary to the TaskManager through *global_vars*.  
+Schedule a custom python method *job* with an optional *delay* in seconds. Skip scheduling of tasks for files and/or directories according to *files* and *dirs* arguments. If there already is a scheduled task, re-schedule it with *delay*. Use *logname* in log messages. All additional modules, functions and variables that are defined in the config file and are needed within the *job*, need to be passed as dictionary to the TaskManager through *global_vars*. If you want to limit the scheduler to run only one job at a time, set *singlejob* to True.  
 All arguments except for *job* are optional.
 ```python
 # Please note that pyinotifyd uses pythons asyncio for asynchronous task execution.
@@ -71,7 +71,8 @@ task_sched = TaskScheduler(
     dirs=False,
     delay=0,
     logname="sched",
-    global_vars=globals())
+    global_vars=globals(),
+    singlejob=False)
 ```
 
 ### ShellScheduler