ignore DScardSigner.properties in order to keep PINs private
Refactoring: rename getTagField() to getTlvDataObject()
Add varargs to create/add TlvDataStructures with multiple children
Introduce TlvTagIdentifier as segment of TlvPaths

This new class allows the specify TlvTag occurences on finer granularity
implement testGetTlvDataObject_secondOccurence()
remove obsolete code
Add missing tests and required implementation

* check behavior if specified occurence does not exist
* check usage of TagIndentifiers from within a TlvPath
* TlvDataObjectContainer.getTlvDataObject(TlvPath, int) relies on
getTlvDataObject now to reduce code duplication
remove obsolte methods

TlvDataObject.isPrimitiveTLVObject() and isConstructedTLVObject are used
only to chekc the object type before casting. This is better implemented
using the instanceof operator to ensure that the cast works without
problems. Beside of this usecase the two methods are obsolete and now
removed.
Cleanup TlvDataObjectContainer.removeTlvDataObject(TlvPath)
Clarify constraints on object strucutre in JavaDoc
Cleanup TlvSpecificationContainer.getIndexOfSubTag()
Review
Code cleanup
Accept suggestion for variable renaming to noOfPreviousOccurrences
Merge pull request #33 from alexfupp/tlvPathSelectionByOccurrence

Tlv path selection by occurrence