Allow HTTPS and full URLS for V1Meta and V1Client

allow specifying URL scheme, thus allowing HTTPS.  Optionally, rather
than the separated-out args, take an instance_url constructor keyword
for V1Meta and V1Client that will be parsed.

Conflicts:
	v1pysdk/client.py
performance enhancement to query.Attr syntax
Enhance logging of HTTP calls and errors
Remove redundant text from string representation
correct examples for new recommended calling style. Removed bad examples.
Update readme and bump version
Merge pull request #9 from bazsi/master

v1meta: return NoneDeref instead of None when a reference is broken
Add Content-type headers for requests
Fix a mistaken __getattr__ later when this variable is looked for
ntlm: raise HTTPErrors when appropriate. Fixes issue #3

It turns out that the ntlm auth handler provided by python-ntlm
doesn't handle http error codes. To work around this I created a
subclass of HTTPNtlmAuthHandler that calls the 'error' method of
it's parent if a non-200 status code is returned.
Update readme
Updates to README
Fix XML syntax for setting multi-valued relations
Version bump
BaseAsset: don't save the AsOf date as data

Since the assets don't contain an actual AsOf data field in their
meta definition, it is not enough to simply put it into the data
dict. AsOf is a plain old attribute, not affected by the getattr magic
going on.
BaseAsset: make it possible to get derived values

Sometimes we query values that don't exist as fields within the
respective object, like using @MaxDate and such things. These are not
accessible by simple attribute access, as we can't encode the at sign
within Python attribute names.

Still, we want to access these too. My solution was to add a get_derived()
method to BaseAsset, this method gets an attribute name as a string, solving
this mapping problem.

For now (lacking a better understanding on my part), all attribute names
that contain '@' or '[' are assumed to be derived values that can't
be attribute accesses.
V1Query: allow selecting values with filters

The select() method didn't like filters in select() expressions, which
this patch fixes by checking if the selected attribute contains a '[' or
not.

This allows stuff like:

Scope.ParentMeAndUp[Parent.Name='System (All Projects)'].Name


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