Add url,user,password to LiquibaseProperties

User can set those properties (optionally) to use a different
DataSource than the default.

Fixes gh-1558
Add additional class conditions for JTA auto-configuration

Previously, JTA auto-configuration would fail with a variety of
ClassNotFoundExceptions and NoClassDefFoundErrors if it was used with
an “incomplete” classpath. This commit adds a number of classes to
@ConditionalOnClass annotations so that the auto-configuration backs
off gracefully in the absence of certain classes.

Specifically, the following now work as expected:

 - Deploying an app to a server with JTA available via JNDI when the
   app does not use transactions
 - Auto-configuration of Atomikos without JMS
 - Auto-configuration of Bitronix without JMS

Both XADataSourceAutoConfiguration and JndiDataSourceAutoConfiguration
have been updated to back off in the absence of spring-jdbc; a
dependency of DataSourceProperties which is used by both classes.

Error handling in AtomikosDependsOnBeanFactoryPostProcessor and
BitronixDependentBeanFactoryPostProcessor has been enhanced so that the
correct dependencies are established, even in the absence of JMS.

Fixes gh-1538
Merge branch '1.1.x'
Provide group in ResolvedArtifactLibrary to enable discrimination

The fix for gh-1475 introduced the use of an artifact's group to
discriminate between two libraries with the same name (artifact id)
and version. However, in the case of Gradle, a group name was not
provided for libraries that have been resolved from a repository.

This commit updates ResolvedArtifactLibrary to use the group obtained
from the underlying ResolvedArtifact as its discriminator.

Fixes gh-1543
Merge branch '1.1.x'
Document build-time property expansion using Gradle

Closes gh-1540
Merge branch '1.1.x'
Reinstate repository configuration in spring-boot-samples pom

The repository configuration is there in 1.1.x but missing in master.
This commit brings the two branches back into line.

Closes gh-1473
Polish
Merge branch '1.1.x'

Conflicts:
	spring-boot-docs/src/main/asciidoc/howto.adoc
Tweak PoolingDataSourceBean.getParentLogger()

Update PoolingDataSourceBean.getParentLogger() to directly call the
method rather than use reflection. Also removed the logic from
`DirectXADataSource` since any fix there should really be applied in
the DataSource being wrapped (and not the wrapper).

See gh-1518
Polish
Polish Redis sentinel support
Allow Jackson features to be configured via the environment

Enhance JacksonAutoConfiguration to configure features on the
ObjectMapper it creates based on the following configuration
properties:

spring.jackson.deserialization.* = true|false
spring.jackson.generator.* = true|false
spring.jackson.mapper.* = true|false
spring.jackson.parser.* = true|false
spring.jackson.serialization.* = true|false

The final part of each property name maps onto an enum. The enums are:

deserialization: com.fasterxml.jackson.databind.DeserializationFeature
generator: com.fasterxml.jackson.core.JsonGenerator.Feature
mapper: com.fasterxml.jackson.databind.MapperFeature
parser: com.fasterxml.jackson.core.JsonParser.Feature
serialization: com.fasterxml.jackson.databind.SerializationFeature

Closes gh-1227
Add support for configuring RemoteIpValve’s internalProxies

Closes gh-1522
Merge branch '1.1.x'
Improve error handling in EnableAutoConfigurationImportSelector

Previously, EnableAutoConfigurationImportSelector assumed that it
would always find auto-configuration attributes from an
@EnableAutoConfiguration annotation. This assumption does not hold
true in certain circumstances, although exactly what those
circumstances are is unclear. It could occur if the import selector
were used directly, but it's package-private making that unlikey. In
such circumstances a NullPointerException was being thrown.

This commit asserts that the attributes are non-null and, should the
assertion fail, produces an error that is more helpful than an NPE.

Closes gh-1512
Merge branch '1.1.x'
Use ErrorController.getErrorPath() to ignore the error path for security

Fixes gh-1548 again
Merge branch '1.1.x'