DISPATCH-56: Introduce Json/AMQP friendly schema and config file parsing.

Added qpid_dispatch_internal.management package with the following:
- schema.py: manipulate general purpose json schema for management entities.
- Schema.validate(): verifies attribute values, adds default values, and enforces
  required/unique/singleton constraints in the schema.
- entity.py: represent management entity instances with attribute values
- qdrouter.json: json schema for the dispatch router.
- qdrouter.py: parse qdrouterd.conf into a Schema.

These classes are intended to replace config.schema and config.parser,
they are more general and more JSON/AMQP friendly.

They are not yet wired into the C router.

The config file parser introduces some minor change to config file format to
accomodate the AMQP requirement that all entities have name and identity
attributes:
- all sections (entities) can have name and identity attributes as per AMQP spec.
- sections without explicit name/identity attributes are given defaults.
- section router: "router-id" replaced with "identity"
- section log: renamed "logging"
- section log: "module" replaced by "name"
- section listener/connector: "label" replaced by "name"

git-svn-id: https://svn.apache.org/repos/asf/qpid/dispatch/trunk@1598667 13f79535-47bb-0310-9956-ffa450edef68