Order redcap_api and _csv fields within project

Change the behavior of the fields methods on Clients in redcap_api and
redcap_csv backends to generate order properties that are relative to
the project node, rather than the immediately superior section node.
This is consistent with the field order tracked by the redcap database
itself and therefore what is returned by the redcap_mysql backend.

Fixes #24
Merge pull request #25 from aaron0browne/order

Order redcap_api and _csv fields within project
Update README with better description and example

The Neo4j export example has been removed now that Origins relies
on the facilities in graphlib.
Implement CSV readers that decode byte strings to unicode
Implement indexer module

This includes functions to build the initial index given a set of
known relationships, crawl the index to store references between each
pair of elements, and resolve the references by producing the paths.
Move constant definition in tests to package level
Update tests to use Neo4j 2.0.3

Signed-off-by: Byron Ruth <b@devel.io>
Change relative import to absolute

The test suite starts inside the `tests` package already, so the
relative import is invalid.

Signed-off-by: Byron Ruth <b@devel.io>