Issue #4533 was supposed to make BasicBatchConfigurer public again but
unfortunately only the class visibility was changed. This commit makes
sure it can be overridden.

Closes gh-4888

Update the Oomph instructions.

Closes gh-4844

* pr/4867:
  Fix invalid port number in doc

Closes gh-4867

By type is too restrictive and surprising for users who wanted to add their
own MetricReaderPublicMetrics for other reasons.

Closes gh-4839

# Conflicts:
#	spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/websocket/WebSocketAutoConfiguration.java

Tomcat's websocket support requires Java7 or later. That commit makes
sure to register its support only when such requirement is met.

Closes gh-4846

Clarify that "spring.config.*" properties doesn't work in configuration
files.

Closes gh-4838

* pr/4829:
  Change redirect in initscript to support old bash

`&>>` syntax is bash version 4. This fix allows to support older
versions.

Fixes gh-4820
Closes gh-4829

* pr/4837:
  Polish test

Closes gh-4837

See gh-4809

See gh-4789

when the logname is empty it replaces it with the root logger name.

Fixes gh-4808

* pr/4806:
  Fix typos

Closes gh-4806

Closes gh-4786

ExitCodeGenerators is not going to be immediately used by spring-task so
it can remain package-private for now.

See gh-4757

Closes gh-4792

Closes gh-4644

Previously, the worker used non-daemon threads which meant that they
prevented the JVM from shutting down. Ideally, we’d avoid this problem
by closing the worker and access log receiver as part of stopping
Undertow, however, due to an apparent bug in Undertow [1], it’s not
possible to do so cleanly.

This commit configures the access log worker to use daemon threads so
that they do not prevent the JVM from shutting down. Unfortunately,
this means that the threads will still be running after the context has
been closed but before the JVM shuts down but that appears to be
unavoidable due to the aforementioned Undertow bug.

Closes gh-4793

[1] https://issues.jboss.org/browse/UNDERTOW-597

This reverts commit 00ba7bea.

See gh-4786

Fixes gh-2872