Libwandder 2.0.15

• ETSILI: add new API methods -- wandder_etsili_get_encryption_container() and wandder_etsili_get_integrity_check_contents()
• Fixed decoding error when items were using an indefinite length field.
• Added new tag type and class to represent content that had already been encoded: WANDDER_TAG_ALREADY_ENCODED and WANDDER_CLASS_ALREADY_ENCODED
• When converting a sequence of integers to a string, add an ellipsis at the end of the string if the buffer is not large enough to fit all of the numbers in the sequence.
• Fix incorrect decoding of sequences of primitive types.
• Fix memory leak of content that was copied by a decoder inside init_wandder_decoder()