a MetadataArgs object
let's assume for a moment that this works
making progress on replacing the metadata args
make the new MetadataArgs object work, all tests now pass
import the metadata args in the main module
remove unused imports
fix docstring
remove unused import
fix the docstring
Merge branch 'feature/objectify_MetadataArgs'

* feature/objectify_MetadataArgs:
  fix the docstring
  remove unused import
  fix docstring
  remove unused imports
  import the metadata args in the main module
  make the new MetadataArgs object work, all tests now pass
  making progress on replacing the metadata args
  let's assume for a moment that this works
  a MetadataArgs object
activate python3 tests via travis
fix all relative imports to be py3 compatible
fix StringIO import to be py3 compat
iteritems missing in py3
use seek(0) instead of reset()

The BytesIO class seems not to have a reset().
py3 string type
py3 int types
fix use of xrange, now using six
make the magic a byte immediately
make the empty string and empty byte