Added QblKeyFactory for easy recreation of keys with modulus and exponents
* removed bidirectional associations of config classes
* corrected config class structure in general
* changed ConfigSerializationTest to adapt the new class structure
corrected comments of class associations
Added BlockingQueue to DropController
Merge pull request #80 from L-Henke/QblKeyFactory

Nice work. Thanks
Merge pull request #90 from f-porter/Issue69-Fix-Config-Class-Structure

Corrected config class structure
ModuleManager: rename initModule() to startModule()
ModuleManager:

Modules are now started in their own background thread. They must make sure,
that they lock configs by itself to avoid race conditions.
Merge pull request #81 from Gottox/master

ModuleManager
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