minor fixes
code cleanups
DragNBatch

- ADD: settings progress values and status text by plugins
added EventLogger class
Streams

- FIX: RandomByteStream was abstract instead of sealed
- CHG: code cleanups
code cleanups and improvements
minor fixes
code cleanups
code cleanups
commands

- CHG: moved command types to separate namespace
- CHG: code cleanups
job framework

- ADD: started to implement job framework
- CHG: code cleanups