Merge pull request #14 from aaron0browne/master

Extend and synchronize redcap backends fixes #13
Add support for retrieving foreign keys with the MySQL client
Add support for retrieving foreign keys with the SQLite client

As noted here: http://www.sqlite.org/foreignkeys.html#fk_enable, not all
databases support foreign keys. However unless SQLITE_OMIT_FOREIGN_KEY
was included during compilation of sqlite, the foreign_key_list pragma
will still list the foreign keys even if they are not enforced.
Add support for retrieving foreign keys with the Oracle client
Add support for specifying the non-default schema in the Oracle client

This will query the `ALL_*` tables when fetching the tables or views
Remove trailing whitespace
Merge pull request #15 from aaron0browne/master

Introduce sections into REDCap hierarchy
Merge pull request #16 from aaron0browne/master

Clean up the redcap section class addition
Abstract out graph properties API into base class
Implement __eq__ for Nodes and Rels classes to ignore the type

This compares the contents of the containers.
Return a distinct set of nodes in Rels.nodes()
Use copy to prevent iterating over a changing set
Implement Props __bytes__, __unicode__, __repr__ and __cmp__

All use the `id` to uniquely identity the object.
Update tests for API changes and additional coverage
Add coveragerc
Use 'Origins' as base label for Neo4j nodes

This ensures nodes created by Origins are differentiated from other
nodes in the graph. A section to the README has been added to denote
this change and how to utilize a unique constraint on the `uri` property.
Add additional SQLite client tests
Ensure the result of Nodes.match is sorted

The provides a bit more predictable output for use and test purposes.
If the order is necessary to be maintained, this can be reverted.
Increase the log level during tests to prevent polluting the output
Fix graph tests to not use hard-coded node ids