jobs, extension methods and code cleanups

- ADD: Dispatcher property to DispatcherJobScheduler
- ADD: Invoke() extension method for DispatcherObject based classes
- CHG: code cleanups
minor changes for JobScheduler (based) classes
jobs

- ADD: jobs can be executed now
- FIX: documentation fixes
- ADD: WinForms based job scheduler
- CHG: using Timer from System.Threading namespace for JobScheduler
class now
jobs

- CHG: IJobExecutionContext .ResultVars => IJobExecutionContext .Result
- CHG: code cleanups
- ADD: interface for describing job schedulers
jobs

- ADD: Executed event to IJobScheduler
- CHG: moved JobProvider delegate
fixes, cleanups, improvements, sessions and NotificationObjectBase

- ADD: types for handling sessions
- ADD: ReceiveValueFrom attribute to receive (new) values from
properties
- FIX: use of enumerator in CollectionHelper.Concat() method
- CHG: code cleanups and improvements
updated and fixed concept of handling options of Receive*Attributes
NotificationObjectBase

- UPD: concept of options for Receive*Attributes
- CHG: code cleanups and improvements
NotificationObjectBase

- ADD: SetProperty<T>() method event for pre .NET 4.5 systems
code cleanups