Code fixes, test fixes, and python 3

Hello,

skiff almost works on python 3, it just needs one change (`dict.iteritems` to `dict.items`). In the process of making that change I needed to make some other fixes to the code & test suite:

* `nyc1` isn't available right now, need to use `nyc2`
* `mysuperrandomdomainname.com` seems tied to your account, each person who runs the test suite needs to pass in their own domain
* the `Image.get` search functionality wasn't working
* the pagination tests were looking for 10 items, but it seems 20 are returned by default
* `Domain.delete_record` wasn't being called with the right signature

Tests now pass on 2.6, 2.7, and 3.4:

```
$ DO_TEST_DOMAIN=... DO_TOKEN=... ../py26_env/bin/py.test
=========================== test session starts ============================
platform linux3 -- Python 2.6.9 -- py-1.4.23 -- pytest-2.6.1
collected 15 items

test_skiff.py ...............

======================= 15 passed in 1815.96 seconds =======================

$ DO_TEST_DOMAIN=... DO_TOKEN=... ../py27_env/bin/py.test
=========================== test session starts ===========================
platform linux2 -- Python 2.7.4 -- py-1.4.23 -- pytest-2.6.1
collected 15 items

test_skiff.py ...............

======================= 15 passed in 1488.83 seconds =======================

$ DO_TEST_DOMAIN=... DO_TOKEN=... ../bin/py.test
=========================== test session starts ===========================
platform linux -- Python 3.4.1 -- py-1.4.23 -- pytest-2.6.1
plugins: xdist
collected 15 items

test_skiff.py ...............

======================= 15 passed in 1320.63 seconds =======================
```

Let me know what you think.

-Steve