Allow `original_url` to behave as an attribute like `method` already does. Remove the `original_url` from the test to avoid confusion.

Note: working with __getattr__ and __setattr__ this way is problematic. Those attributes exist on the Url class, not AttrDict. So while this is an improvement, it's perpetuating bad behavior.
Simplify the __unicode__() method.
Pythonify the tests.

- break out and add some new tests
- use assertEqual()
- use setUp() instead of __init__()
- remove the ValueError on missing self.key that will never be reached
- use assertRaises() for exception testing
Test to check the dict (and nested dictionaries) can be JSON serialized. This test fails.
UserDict - no reason was given for reimplementing a core Python data structure. Furthermore, the custom AttrDict doesn't JSON serialize so an object built from JSON cannot be serialized back to JSON.

**BREAKS BACKWARD COMPATIBILITY.** This is now a real Python dictionary and *no longer has attribute access* for the data. This could be added back, but it's un-pythonic and introduces complexity. UserDict retains the ability to access `data`. The `dict` property is gone.
Add a test to ensure that object attributes don't collide with dictionary data.
Specify package version only once. Use it in the User Agent string (instead of the out-of-date, hardcoded version #). PEP8 setup.py.
Merge pull request #14 from joncotton/tidy

Pythonify and enhance the tests.
Merge branch 'use_dict_not_custom_class' of https://github.com/joncotton/embedly-python into joncotton-use_dict_not_custom_class

Conflicts:
	embedly/models.py
	embedly/tests.py
Merge pull request #16 from joncotton/canonical_version

Specify the package version only once
Update Readme
Merge branch 'master' of github.com:embedly/embedly-python

Conflicts:
	embedly/__init__.py
	setup.py
Fixes for python3
Fix JSON serialization
Remove unneeded override of Url#__get_item__
Fix __version__ import.

There were circular import issues most notably during install. `setup.py` now grabs the version information without having to import the module (which led to importing other modules which isn't appropriate during setup.py activities).
Tidying - reorder params and add a documentation line for third param.
Merge pull request #19 from joncotton/fix_version_import

Fix version import. `__init__.py` is the canonical location
Merge pull request #18 from se3000/master

additional serialization tests (a part of this initial PR was reverted; now it's just more test data)
Fix testing in Python 2.6