Merge pull request #4 from bazsi/master

please pull my patches to greatly speed up v1pysdk
adds HTTPCookieProcessor to URL opener handlers

Provides auth ticket cookie after first successful request per Best
Practice advice in Data API documentation.

[fixes versionone/VersionOne.SDK.Python#6]
Merge pull request #7 from jeremy-w/http-cookies

adds HTTPCookieProcessor to URL opener handlers
Merge remote-tracking branch 'origin/pr/5'
Include AsOf data item in data dict as well as attribute
v1meta: return NoneDeref instead of None when a reference is broken

When a reference is broken, the asset object contains a None as a value
of the attribute. The issue with this is that call sites will have to
check unresolved references explicitly, e.g. if I wanted to write:

story_name = story.Scope.Name

I would have to check the Noneness of story.Scope before dereferencing
story.Scope.Name, like this:

if story.Scope:
    story_name = story.Scope.Name
else:
    story_name = None

This patch changes that, if a reference would become None, it results in
an object that behaves like a None but call-sites can continue to dereference
attributes within that.

Signed-off-by: Balazs Scheidler <bazsi@balabit.hu>