Composed a brainstorming document for proper MVC implementation.

I proposed to move the scannerstrategies package out of the control
package. Moreover I  introduced new control classes for handling
IconSet instances and routing operations that can be applied on such.
The last paragraph deals with the inter class communication and 
especially inter package communication, to define a stricter MVC 
design.
Marked "obsolete" brainstorming documents as such.

I left them in this folder as they are intended to give others the chance
to reproduce my "chain of thoughts".
Restructured the UML diagram to display the improved MVC design.
Updated the roadmap to indicate what steps are to be taken next.
Moved the class diagram on top of the GUI mockup.
Moved scannerstrategies out of the control package.

They do not really incorporate the functionality of control
classes as defined by most MVC interpretations.
First draft implementations of Coordinator and IconSetOperator.

No operations on IconSets are included yet, but only the basic
class hierarchy.
Added an openIconSet() function that displays a filechooser.
Removed dependencies of model classes other than 'access' package.

Looking at the class diagram, one can recognize, that the view
classes are in fact unaware and independent of the model classes.
The only model classes that provide data for display reside in
the 'access' subpackage.
Removed the hardcoded opening mechanism.

To be replaced by a proper call to the Coordinator class.
Began a first implementation of the signal/slot mechanism.
Added access model instances to IconSetOperator.

As IconSetOperator maintains all relevant objects that belong to one
specific IconSet instance, it makes sense, that this class also
instantiates and owns the corresponding IconSetModel and
ClassificationTreeModel instances.
Made actual use of the newly created class hierarchy to open IconSets.

Signals and Slots are being used to establish the communication
betweenMainWindow and Coordinator. IconSetOperator properly loads
the IconSet instance and offers getters to its access model classes,
which deliver data to the view.

Thereby the basic MVC structure has been prepared. Next steps
include the implementation of a mechanism to track the active IconSet
inside the Coordinator class.
Wrote additional documentation for the new classes and functions.
Specified the communication between IconSet and its access objects.

Proposed the usage of the observer pattern, by which an update
function within the IconSetObserver has to be called, that then
emits the dataChanged signal.
Updated the UML to reflect the recent changes and new plans.
Implemented the observer pattern for IconSet.

Has to be tested as soon as the first operation on IconSets has been 
implemented.
Updated readme files to reflect the current state of development.
Added a "Delete Icon" toolbar button to MainWindow.

The corresponding actionIconDeleteIcon() slot gets called when the 
Action has been triggered.
Added a deleteIcon() function to the IconSet class.