Previously `spring.velocity.charset` only controlled the output encoding
with the templates being loaded with the default encoding. We now
consistently set the same value for both the input and output encodings.

It is still possible to override it to a different value using
`spring.velocity.properties.input.encoding`

Closes gh-3994

E.g. just adding Dropwizard to the classpath switches it off which
might be surprising. We need a @ExportMetricReader to do the export.

Closes gh-4053

Closes gh-4050

We need to be a bit cautious about whether Spring Security is on
the classpath or not, but if it is we can test for the admin role
(as specified in `management.security.role`).

Fixes gh-4060

This change applies only to "standard" MVC endpoints (not the extended
ones like /env and /jolokia which already have this feature). Allows
users to supply an endpoints.{name}.path.

Fixes gh-2790

This commit adds two new properties, spring.devtools.remote.proxy.host
and spring.devtools.remote.proxy.port that can be used to configure
RemoteSpringApplication to connect to the remote application through
an HTTP proxy.

Closes gh-3968

This commit adds support for configuring defaultValue and
emptyStringIsFalse to MustacheCompilerFactoryBean.

Closes gh-4057

Closes gh-4018

Update `ServerProperties` to automatically enable `use-forward-headers`
when running on a cloud platform.

A new `CloudPlatform` enum has been introduced that detects Heroku and
Cloud Foundry.

See gh-4018

Add a new `server.use-forward-headers` property which can be used to
switch on X-Forwarded-For header support in all supported embedded
servlet containers.

This commit reverts the decision to enable `RemoteIpValve` with Tomcat
by default (gh-3782) and requires that either `user-forward-headers` is
set to true or that `server.tomcat.protocol-header` or
`server.tomcat.remote-ip-header` are set.

See gh-4018
See gh-3782

Add a `useForwardHeaders` property to allow embedded Undertow
containers to respect X-Forwarded-For headers.

Fixes gh-3881

Add a `useForwardHeaders` property to allow embedded Jetty containers
to respect X-Forwarded-For headers.

Fixes gh-3802

Update Abstract & Tomcat EmbeddedServletContainerFactoryTests to check
that X-Forwarded-For headers work as expected.

See gh-4018

Update ManagementWebSecurityAutoConfiguration to reinstate lazy creation
of EndpointHandlerMapping from the EndpointPathRequestMatcher.

Fixes a regression introduced in eb298478 and picked up my one of the
sample integration tests.

Fixes gh-4059

See gh-4068

After the ApplicationEnvironmentPrepared we now check that the
webEnvironment flag and/or the Environment hasn't changed, in case
the user wanted to switch the context from a web to non-web in a
listener.

Fixes gh-2716

In order to have more control on the structure of the configuration, we
do not bind to `RepositoryRestConfiguration` directly anymore. This
commit introduces `RepositoryProperties` instead.

See gh-3854
Closes gh-4073

Takes into account the fact that the new /actuator endpoint sometimes
loses its path (it is "" relative to a non-empty management context path).

Fixes gh-4059

* pr/4069:
  Polish

Closes gh-4069

Update devtools to detect JRebel and disable application restarts. Other
features (such as LiveReload) can still be used.

Fixes gh-3095

For logback we also support logging.pattern.level as a synonym.

Fixes gh-4062

Closes gh-4049

Closes gh-3949

Previously, a `NoClassDefFoundError` could be thrown if EhCache or Guava
is on the classpath without `spring-context-support` as the respective
cache statistics provider both needs the implementation and the spring
abstraction implementation.

The `@ConditionalOnClass` definition has been updated to properly guard
those beans.

Closes gh-3960