Undertow 1.1 expects that DeploymentInfo.contextPath is set to "/" for
a root context. If it is left as "" the session cookie path is not
correctly set. See UNDERTOW-350 for background.

This commit simplifies the original work-around committed in 78c22813.

Fixes gh-2065

See gh-1736

Fixes gh-1736

Add deployment tests for Tomcat, TomEE and WildFly to ensure that
a basic Spring Boot application can be deployed to a traditional
Application server.

Since the deployment tests can be quite slow, they currently only
run in the "full" build profile.

Fixes gh-1736

Update SpringBootServletInitializer to automatically add itself as a
SpringApplication source if it is annotated with @Configuration.

Also throw a more meaningful exception if no sources have been
configured.

Fixes gh-2073

Update JndiConnectionFactoryAutoConfiguration to ensure that the
JmsProperties bean is created. Prior to this commit deployment to
a WildFly would fail with a NoSuchBeanDefinitionException.

Fixes gh-2072

Fixes gh-1750

Closes gh-2061

Closes gh-2062

Conflicts:
	spring-boot/src/main/java/org/springframework/boot/logging/LoggingApplicationListener.java

Extract some of the common property keys as constants.

Fixes gh-2068

Replace `classpath:db/migrations` with `classpath:db/migrations`.

Fixes gh-2063

Explicitly set a ServletSessionConfig when the context path is "". This
is a workaround for UNDERTOW-350 to ensure that the session cookie path
is correctly set.

Fixes gh-2065

Fixes gh-2066

Previously, specifying a simple target name for a regular project would
store the (zip) archive in a file matching the target name. Only adding a
slash at the end of the name allows to extract it as a directory. It
turns out that such convention is not easy to catch and if a simple name
is provided on the command-line, the user probably wants to create a
directory with such a name with the content of the project.

Note that if a build file is required and the name does not have any
extension, we still store a file with the required name as auto-detecting
the extension to use is not that easy.

Fixes gh-2056

See gh-2028

Fixes gh-2028

Add a `spring.mvc.set-ignore-default-model-on-redirect` property to
allow RequestMappingHandlerAdapter.setIgnoreDefaultModelOnRedirect to
be easily customized and change the default value to 'true'.

Fixes gh-2018

Drop the setAdditionalProperties method from ShellProperties to ensure
that it is not included in the meta-data JSON. The additional properties
are usually wired in using @Autowired and it is pretty unlikely that
anyone is using the setter directly.

Fixes gh-2055

Fix YamlPropertySourceLoader to correctly flatten keys merged from
different documents.

Closes gh-2022

See gh-1996

Previously, a property holding an array did not have a proper default
value in the meta-data even though the related field was initialized
properly.

An explicit support for arrays has been added. The "defaultValue" now
holds the default value for singular properties or an array of values for
array-based properties. If the value is initalized with an empty array,
the default value is an empty array as well.

Closes gh-1996

Fixes gh-1439

Previously, any valid property was added to the meta-data of the current
group. This can be annoying for types that are not meant to be bound from
a simple string value. ClassLoader is one example.

A list of well-known types has been added: if the property type matches
an element of this list, it is ignored.

Fixes gh-2012

Fixes gh-2041

Update YamlPropertySourceLoader to use a MapPropertySource rather than
a PropertiesPropertySource to ensure that the underlying order is
retained.

Fixes gh-2022

Upgrade to the SNAPSHOT so that CI will catch any problems early.

See gh-2038

Add ConfigurationWarningsApplicationContextInitializer to report
warnings for common configuration mistakes. Currently the initializer
will log a warning if @ComponentScan is used on a @Configuration class
in the "default" package.

Fixes gh-2050