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 support for performing validation of individual elements of a collection (#470)
Adding a test to confirm behavior of a nested list
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
Update core.rst

Configuration example needs to provide property naming to match the yaml example.
Merge pull request #479 from christophercurrie/patch-1

Update core.rst
Merge pull request #456 from cmicali/master

Add ability to override config settings that are in arrays and maps
Fixed org.eclipse.jetty.server.handler.AbstractHandler warnings
Merge pull request #468 from dropwizard/feature/bootstrap-validator-factory

Make ValidatorFactory available on Bootstrap
Merge pull request #482 from jhalterman/master

Fixed org.eclipse.jetty.server.handler.AbstractHandler warnings
Merge pull request #471 from mveitas/validation-collections

Add support for performing validation of individual elements of a collection
[maven-release-plugin] prepare release v0.7.0-rc2
[maven-release-plugin] prepare for next development iteration
Deprecate the defaultReadOnly property in favor of readOnlyByDefault
Merge pull request #486 from celkins/default-read-only

Deprecate the defaultReadOnly property in favor of readOnlyByDefault