No pack() and unpack() methods for InterfaceStatistics and NameResolution

[rpp0]

When iterating over pcapng blocks using PcapngReader, the reader will fail when an InterfaceStatistics or NameResolution block is encountered:

  File "/foo/pcapng/reader.py", line 216, in _parse_block
    return NameResolution.unpack(blk.contents, self._endianness)
AttributeError: type object 'NameResolution' has no attribute 'unpack'

[rshk]

(See #2)

BTW, if you have some relevant examples of pcapng files with those blocks, it would be handy if you could put them somewhere so I can integrate them in the unit tests (was thinking about using a separate repo for example pcapng files.. the goal is finding ones that would break the library, and store them along with the name/version of the program which generated them).

[rshk]

This is fixed with new refactoring (in progress). Pending close as soon as refactor branch is merged