* changed collections in config container classes to final
* collections will be instantiated while container class instatiation.
* implemented add() method in config container classes
* changed call of add() method in using classes
* modified getter methods in config container classes to return unmodifiable collections in order to prevent direct write access to them
new class:
* QblPrimaryKeyPairTypeAdapter
new class:
* QblKeySerializationTest
-> test is not working yet as there is missing a proper equals() method for QblPrimaryKeyPair
Added equals method to QblPrimaryKeyPair and its contained classes:
* QblEncKeyPair
* QblPrimaryPublicKey
* QblPublicKey
* QblSignKeyPair
Made test for QblPrimaryKeyPair serialization working
Revert "Issue108 implement add method"
* implemented add() method in config container classes
* changed call of add() methods in using classes

* changed collections in config container class to final
* collections are instantiated during container class instantiation

* modified getter methods in config container classes to return unmodifiable collections in order to prevent direct access to them
New class:
* QblPrimaryPublicKeyTypeAdapter
added test for QblPrimaryPublicKey serialization
Update Change number of drops in Identity class
Fixed  Identity constructor should set QblPrimaryKeyPair #128