fixes #30; follow MARC-to-JSON proposal

There was a critical bug in the serializer previously, that missed
repeated subfields. This commit updated `record.as_dict` so that it

* serializes a MARC record in JSON according to the format proposed under
  http://dilettantes.code4lib.org/blog/2010/09/a-proposal-to-serialize-marc-in-json/
Merge pull request #31 from miku/issue-30

fixes #30; follow MARC-to-JSON proposal
upped version
default missing ind1 and ind2 to blank

Should be fully backward compatible.

I am given library data which contains records like

```
<marc:datafield tag="946" ind1=" " ind2=" ">
    <marc:subfield code="a">No</marc:subfield>
  </marc:datafield>
  <marc:datafield tag="949">
    <marc:subfield code="a">Article</marc:subfield>
  </marc:datafield>
```

(missing `ind1` & `ind2` in 949), which makes `map_xml()` parsing fail with `KeyError: (None, u'ind1')`.
Make installation options more clear
Merge pull request #34 from lbjay/master

super minor tweak to make a clear distinction between the two installation options
no longer bundle ez_setup.py and give instructions for downloading setuptools in README.md fixes #35
resolved doc conflict
Merge pull request #33 from piskvorky/patch-1

default missing ind1 and ind2 to blank