Closes gh-3752

Closes gh-3760

Closes gh-3751

Closes gh-3756

On start.spring.io, if you customize the artifactId it creates a zip file
with the same name. The `spring init` command did not have a similar
shortcut.

This commit updates the request to customize the artifactId if none is
set and a custom location was specified. Just as we check for the
presence of a dot to figure out if we have to extract the archive or not,
we check for it to generate an artifactId without an extension.

In practice, `spring init foo` creates a foo directory with a project
whose artifactId is `foo` and `spring init foo.zip` stores a foo.zip
file with the same project (i.e. the artifactId is `foo`).

Closes gh-3714

The `spring.datasource.name` property was hidden behind the 'name'
attribute of the Tomcat connection pool (since we are mapping all
datasource implementations on the `spring.datasource` namespace.

This commit replace the injected value by hand with the use of the
regular `DataSourceProperties`. That way, we generate proper meta-data
for it as well.

Closes gh-3755

A new `spring.datasource.type` property can now be used to configure the
connection pool implementation to use (rather than only relying on Boot's
preferences).

Closes gh-3705

Improve the documentation to explain the necessary steps to create a
custom Spring Boot starter. In particular, provide more details regarding
naming conventions.

Closes gh-2537
See gh-2927

* pr/3750:
  Polish
  Add fallbackToSystemLocale configuration key

Closes gh-3750

Allow to configure the `fallbackToSystemLocale` attribute of
`MessageSource` via configuration.

Closes gh-3749

Previously, to use a custom ConfigurableWebBindingInitializer, it was
necessary to extend WebMvcConfigurationSupport and override
getConfigurableWebBindingInitializer. This had the unwanted
side-effect of switching off the auto-configuration of Spring MVC.

This commit updates the auto-configuration to look for a
ConfigurableWebBindingInitializer bean and register it with Spring
MVC.

Closes gh-2526

Closes gh-3516

Add:

 - jackson-datatype-hibernate4
 - jackson-datatype-hibernate5
 - jackson-datatype-jdk7
 - jackson-module-parameter-names

Closes gh-3727

Closes gh-3738

Previously, PropertiesConfigurationFactory would only create a
DefaultPropertyNamePatternsMatcher that ignored case if it was
ignoring unknown fields. If the binding had a target name and
unknown fields were not being ignored the matcher would consider the
case when finding matches. This meant that SERVER_PORT would not being
to ServerProperties.port as SERVER did not match the target name,
server.

This commit updates PropertiesConfigurationFactory to use a
case-ignoring DefaultPropertyNamePatternsMatcher when binding with
a target name. The tests have also been updated to test binding both
with and without ignoring case and using either Properties or
PropertySources. The above-described matching is only performed
against PropertySources and the bug only occurred when using a target
name, making it important to test all combinations.

Closes gh-3745

The target attribute is effectively checked for null beforehand so this
additional defensive check can be removed.

Closes gh-3725

See gh-3696

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

Following the changes made to combines the /links and /hal endpoints
into a single /actuator endpoint, a web browser accessing /actuator
would receive a 406 response if HAL browser was not on the classpath.

This commit updates the /actuator main entry point so that it will
serve JSON to a web browser when HAL browser is not on the classpath.

The actuator's embedded documentation has also been updated to reflect
the recent changes.

Closes gh-3696

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

See gh-3696

For some reason, we forgot to add an attribute to customize the package
name when using spring init. This is now the case.

Closes gh-3716

See gh-3569

Fixes gh-3527