Added BlockingQueue to DropController
Removed onDropEvent interface from DropListener
Added Javadoc to DropController
Delete core.png (qabel-core issue #67)
Merge pull request #95 from k-c13/uml-class-diagram

Delete core diagram img
Ignore the log directory
Merge pull request #98 from jasinai/IgnoreLogDir

Ignore the log directory
Merge pull request #94 from L-Henke/DropControllerWithBlockingQueue

Added BlockingQueue to DropController
ReceiveMessages returns a Collection<String>
retrieve() now returns a collection

* reformatted code
* removed unneeded method argument
synced test to new changed Drop methods
removed unneded import
Merge pull request #97 from jan-schreib/Multipart

Multipart