* pr/3719:
  Add statsd metric export auto-configuration

Update MetricExportAutoConfiguration to auto-configure statsd metrics
export when a `spring.metrics.export.statsd.host` property is set.

Closes gh-3719

* pr/3915:
  Add Liquibase labels and parameters properties

Update `LiquibaseAutoConfiguration` and `LiquibaseProperties` to add
support for labels and parameters.

Closes gh-3915

* pr/3938:
  Add `git.properties` to default devtools excludes

Update `DevToolsProperties` to exclude `git.properties` files.

Prior to this commit any application configured to write `git.properties`
could trigger unexpected application restarts. The problem is particularly
prevalent when using Eclipse M2E in combination with the
`git-commit-id-plugin`.

Closes gh-3938

* pr/3962:
  Remove duplicate `@ConditionalOnMissingBean` checks.

Closes gh-4004

* pr/4010:
  Fix synchronization issue in OpenTSDBMetricWriter

Closes gh-4010

Relocate several auto-configuration classes to `...autoconfigure.data`
to make it clearer that they are Spring Data specific.

Also moved `EntityManagerFactoryBuilder` to `spring-boot` since it is
generally useful and doesn't need to be directly tied to the
auto-configuration module.

Fixes gh-4002

Closes gh-3913

Exclude spring-boot-starter-validation since those jars are provided
by the container.

Update the spring-boot-autoconfigure POM so that
jackson-module-parameter-names is optional.

See gh-3804

The parameter names module allows users of Java 8 that have compiled
their code with the -parameters option to avoid the name for
annotations to map the json onto constructor and method parameters
with the names of the parameters being used instead.

This commit adds auto-configuration for the module that will only
be enabled when running on Java 8.

Closes gh-3804

See gh-3900

Previously, dev tools would restart the application when any .class
file changed. This included test classes. This commit updates the
default excludes to ignore any classes with a name that ends in 
Test.class or Tests.class.

Closes gh-3900

For the character encoding filter to work, it's vital that it sets
the request's encoding before any other filters attempt to read the
request. This commit updates the order of
OrderedCharacterEncodingFilter to be HIGHEST_PRECEDENCE and improves
the existing test to check that the ordering is as required.

Closes gh-3912

Closes gh-3902

The recommended usage for the java executable is:

    java [-options] -jar jarfile [args...]

This commit updates the default launch script to match this recommended
usage by moving -jar to be the last option, after both the
disableJarChecking system property and any JAVA_OPTS.

Closes gh-3930

Closes gh-3913

* pr/3967:
  Polish Javadoc

Closes gh-3967

Closes gh-3943

See gh-3964