Update SpringBootServletInitializer with a registerErrorPageFilter flag
that can be used to disable ErrorPageFilter registration.

Fixes gh-3603

Update ErrorPageFilter to only handle errors when `response.sendError`
has been called. This should allow custom @ExceptionHandlers to
completely handle errors and return custom status codes without
triggering the "Cannot forward to error page" log message.

The Javadoc for sendError states:

  "The server defaults to creating the response to look like an
   HTML-formatted server error page containing the specified message"

Where as setStatus states

  "This method is used to set the return status code when there is
   no error "

Fixes gh-2745

Update `spring-boot-sample-tomcat-jsp` to include endpoints that trigger
exceptions. Primarily to aid testing of the ErrorPageFilter.

See gh-2745

Update PropertySourcesPropertyValues so that collection values are only
added from a single PropertySource. Prior to this commit, given the
following:

    PropertySource-A
     list[0]=x

    PropertySource-B
     list[0]=y
     list[1]=z

PropertySourcesPropertyValues would take `x` from A and `z` from B,
resulting in a binding of `[x,z]`. The updated code now returns the
more logical `[x]`.

Fixes gh-2611

This reverts commit e04fb155.

Formatting only changed lines doesn't appear to work well.

Using the $home directory seems to be causing intermittent failures on
the CI box.

See gh-3861

* pr/3605:
  Catch more general Hibernate 4.2 LinkageError

Update HibernateJpaAutoConfiguration to catch LinkageError rather than
NoClassDefFoundError. Required due to the fact that JBoss EAP 6 wraps
NoClassDefFoundErrors.

Fixes gh-3605

Update ServerProperties so that unknown SERVER_* environment properties
do not cause startup failures.

Fixes gh-3903

* gh-3926:
  Propagates logback log levels to java.util.logging

Adds the LevelChangePropagator logback listener in order to propagate
Logback's log level changes to java.util.logging loggers.

Logback documentation :
http://logback.qos.ch/manual/configuration.html#LevelChangePropagator

Fixes gh-3924
Closes gh-3926

Update Eclipse cleanup actions to only format changed lines. This will
hopefully help to prevent so many false diffs caused by differences
between Eclipse Luna and Eclipse Mars.

- Update whitespace after inline generics
- Use a more sensible import order
- Update Javadoc warning settings

Update SpringApplicationContextLoader so that setRegisterShutdownHook
is false for tests.

Fixes gh-3763

See gh-3856

Closes gh-3869

Closes gh-3779

Closes gh-3868

Closes gh-3846

Refine commit 8a964814 to set the web environment to false if spring web
is not available in the classpath. Thanks to @mjustin for spotting that
mistake.

Closes gh-3856

Previously, deployment tests were storing the container archives in the
default location (that is `/tmp`) for a total weight of 160MB. In case
the temp directory is cleaned on CI, these have to be downloaded again.

We're now configuring cargo to store these archives in the home directory
instead. This should improve the speed and the stability of the
deployment tests

Closes gh-3861

SpringApplication wrongly expects spring-web to be on the classpath to
figure out whether or not the web environment should be enabled for a
custom context class.

We now properly guard this check so that the web environment is not
enabled (read: not checked) if `spring-web` is not available.

Closes gh-3856

Closes gh-3843

Closes gh-3406
Closes gh-3526

Closes gh-3823

Closes gh-3792

The DataSource health indicator uses `JdbcTemplate` behind the scenes
but nothing was checking that it is actually available.

`DataSourcesHealthIndicatorConfiguration` is now disabled if
`spring-jdbc` is not on the classpath.

Fixes gh-3765

Closes gh-3760

Closes gh-3423

This commit adds support for using the environment to configure the
Freemarker and Velocity view resolvers to allow session overrides.

Closes gh-3410

Closes gh-3421

The annotation processor detects `@ConfigurationProperties` bean or
method definition and merges manual meta-data. The former step will fail
with a NPE if the annotation is not present on the classpath. This could
happen if the annotation processor is added to a module that is not
actually using Spring Boot.

We now have a defensive check that skips that steps but still attempts to
merge manual meta-data if present.

Closes gh-3720

Closes gh-3715

Closes gh-3700

Closes gh-3681

Closes gh-3674