Show Unidirectional Association

[fabiopagoti]

Given
Class A has a reference attribute to class B AND
Class B has no attribute to class A AND
Class A constructor has no importing parameter typed as a reference to class B *1

When
UML code is generated for class A

Then
Relation between classes should be
[A]->[B]
or
[B]<-[A]

*1 See #24 - when a method parameter is a reference to other class the relation should be a dependency not a simple association.