Support for the EVE Api

After calling `lillith.initialize`, call:

```python
lillith.Api.initialize('keyID', 'verificationCode')
```
I have no objections to removing the `_base_url` from the Api class.  I did note that the EVE online API does have another base URL for the test servers.  Keeping the `_base_url` would make it easy to switch to this.  But I have no idea if this is actually useful.

Unless I made a goof, the `_cachetime` parameter is properly hooked in.  The default (if `_cachetime is None`) is to cache a response for exactly the right duration (i.e. use the cachedUntil tag in the response), but `_cachetime` is allows you to override that.