The registry currently only accepts storage driver versions with the
same major version and an equal or lower minor version as its own
current storage driver api version, but this may be changed in the
future if we decide to implement specific version cross-compatibility.
Most conditional parsing code has been moved into UnmarshalYAML
functions for simplicity
Uses the BrianBland fork of goyaml in configuration.go temporarily until
fix https://github.com/go-yaml/yaml/pull/52 is merged in
Custom storage drivers can register a factory to create the driver by
name, similar to the database/sql package's Register and Open
factory.Create returns an in-process driver if registered or an IPC
driver if one can be found, erroring otherwise
This standardizes parameter passing for creation of storage drivers
Also adds documentation for storagedriver package and children