Folder structure change.

The folder structure change has become necessary as we begin to
develop seriously on our project. Furthermore, with the new folder structure
it is better to deploy the application later.
Added PointRef class.

The point ref class should be used where point objects are needed.
The x and y components can be changed by reference instead of by value.
Added triangle class.

An implementation of a triangle is missing yet, but the interface
is here already. Use it for reference.
Extended from "java.awt.Shape"

I forgot to extend the interface from the Shape interface.
Added vector interface.

As the name says, the vector interface represents a vector.
Like the triangle interface, an implementation of a vector is missing yet.
Added vector related interfaces.

These interfaces could be of some help when developing
the new field system for example.
Small additions to PointRef.

Added constructor and a "deepCopy()" method to the class.
Small additions to PointRef

Added methods "getRefX()" and "getRefY()" for returning
the correspondent "DoubleRef" objects.
Before this commit the "PointRef" class was not actually "reference".