Safely ignore services that don't have corresponding ServiceConnectorCreator

This fixes the exception that gets thrown when a NewRelic service is bound to
the app and app attempts to create a service connector (for another service)
specifying only the type
Small cleanup items in README and an exception message.
Fix #9: Use CONFIG level to log failed loading of service connectors
Merged #7
Bump to 0.9.2
Bump to next snapshot (0.9.3.BUILD-SNAPSHOT)
WIP
Support Tomcat's high-performance connection pool

In the process, refactored code towards allowing user-contributable
pool implementation.
Minor documentation update
Refactored cloudfoundry-connector tests to have separate class for each service
Further refactoring to move test data generation closer to each test
Add tests to verify that label-based rabbit payload works fine
Consider AbstractCloudConfig instead of Cloud as service (to turn off auto-reconfig)
Move StubServiceInfo into CloudTest to enable its usage by other projects
Slight refactoring to allow for extending RelationalServiceInfo when
using URIs that don't conform to the expectations of UriInfo.
Minor formatting fixes
Bump to 0.9.3
Bump to next snapshot
Add support for MariaDb driver for mysql service
Bump version to 0.9.4