Throw a ConstraintViolationException for empty resources

Fixes #431
Fix graceful shutdown

Jetty uses StatisticsHandler to track outstanding requests for graceful
shutdown.

See https://bugs.eclipse.org/bugs/show_bug.cgi?id=420142 for more
details.
Merge pull request #433 from joschi/issue-431-IllegalArgumentException

Throw a ConstraintViolationException for empty resources
Make ValidatorFactory available on Bootstrap

`ValidatorFactory` is used to obtain `Validator` instances in several
places (including configuration validation).

Instead of using a singleton instance, let's make this available on
`Bootstrap`, so that validation may be customised (e.g. by `Bundle`s).
Add graceful shutdown test
Merge pull request #467 from vadims/graceful-shutdown

Fix graceful shutdown
Use ephemeral port i DefaultServerFactoryTest

Should make the tests more portable by not relying on an arbitrary port
being free.
Add support for performing validation of individual elements of a collection (#470)
Adding a test to confirm behavior of a nested list
Update testing.rst

Updating information about @Rule annotation in Resources testing
Merge pull request #472 from airborn/patch-1

Updating information about @Rule annotation in Resources testing
config: Add ability to override config settings that are in arrays and maps
config: Add ability to override config settings that are in arrays and maps
Merge branch 'master' of github.com:cmicali/dropwizard

Conflicts:
	dropwizard-configuration/src/main/java/io/dropwizard/configuration/ConfigurationFactory.java
	dropwizard-configuration/src/test/java/io/dropwizard/configuration/ConfigurationFactoryTest.java
	dropwizard-configuration/src/test/resources/factory-test-valid.yml
docs: Updated docs to include notes on config override enhancements
Removing maximum limit on archivedFileCount for file logging.
Merge pull request #474 from reines/remove_max_archivedfilecount

Removing maximum limit on archivedFileCount for file logging.
Use current timestamp for request log events.

Fixes #477.
Use next available tcp port when starting server
Merge ../dropwizard