tlv-hack: Implementing TLV->NDNb and NDNb->TLV conversion of FinalBlockId

Change-Id: Id3f2281dd931b1842ca6338df738958827514302
refs: #1246
tests: Adding unit tests

For now only basic Data packet is checked for conversion consistency

Change-Id: Ib134817cb118756a70c703b3fbb181d855ff409f