All db connection and creation logic is the same, it is just pulled into
a synchronized method so that multiple threads run through the
connection process one at a time.

Fixes #571

* Rabased pull/489/head (@allanbank) to master
* Backed out unnecessary line breaks for 120 char limit
* Enforced checkstyle on new code
  * Was required to make db variable private, updated in tests
  * Removed TODO

Closes #489

Cleaner handling of properties.
Updated documentation of available properties.
Removed default database url.

Making progress towards #539

The version bump required some fixes because of changes to the OrientDB
API as well as to accomodate for changes in thread safety for testing.

Fixes #562

Replaces numeric status codes with a canonical set of Status objects,
each with a short name and description.
Bindings with more specific errors (e.g., timeouts) return additional
statuses.

This changes the default output from messages like:

   [UPDATE], Return=0, 511

To:

   [UPDATE], Return=OK, 511