Upgrade to Spring framework 4.1.1

Closes gh-1654
Fix Jersey1 integration test
Provide native JtaTransactionManager when applicable

This commit updates JndiJtaConfiguration to provide the same detection
algorithm as <tx:jta-transaction-manager>. If a native JTA transaction
manager exists for the current platform, it is used instead of the regular
JtaTransactionManager implementation.

Fixes gh-1576
Make ServerProperties bean conditional on being a webapp
Merge branch '1.1.x'
Change key value if prefix changes

Some weird looking test failures led me to track this down.
If the user changes the prefix for metric names, he probably wanted
to change the keys as welll (otherwise 2 repositories can use the
same key, which is why the test was failing for me). We can do that
in an afterPropertiesSet().
Merge 1.1.x with minor conflict
Merge 1.1.x with minor conflict
Change constructor signature for RedisMetricRepository

Otherwise we had to rely on afterPropertiesSet() being called to
validate and compute the prefix and key (which depend on each
other).
Fix some grammar issues in docs
Merge pull request #1659 from ericdahl/docs-grammar

* docs-grammar:
  Fix some grammar issues in docs
Support Jackson based XML serialization and Jackson2ObjectMapperBuilder

This commit introduces support for Jackson based XML serialization, using the
new MappingJackson2XmlHttpMessageConverter provided by Spring Framework
4.1. It is automatically activated when Jackson XML extension is detected on the
classpath.

Jackson2ObjectMapperBuilder is now used to create ObjectMapper and XmlMapper
instances with the following customized properties:
 - MapperFeature.DEFAULT_VIEW_INCLUSION is disabled
 - DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES is disabled

JodaModuleAutoConfiguration and Jsr310ModuleAutoConfiguration have been removed
since their behaviors are now handled directly by the ObjectMapper builder.

In addition to the existing @Bean of type ObjectMapper support, it is now
possible to customize Jackson based serialization properties by declaring
a @Bean of type Jackson2ObjectMapperBuilder.

Fixes gh-1237
Fixes gh-1580
Fixes gh-1644
Make MetricFilter auto-configuration conditional on OncePerRequestFilter

In addition to requiring the Servlet API to be on the classpath,
MetricFilter requires spring-web to also be on the classpath as it
extends OncePerRequestFilter. This commit updates the auto-configuration
for MetricFilter so that it will be disabled in the absence of a 
dependency on spring-web.

Fixes gh-1664
Merge branch 'gh-1664'
Upgrade to Spring Loaded 1.2.1.RELEASE

Closes gh-1474
Merge branch '1.1.x'

Conflicts:
	spring-boot-dependencies/pom.xml
Polish
Merge branch '1.1.x'

Conflicts:
	spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/repository/redis/RedisMetricRepository.java
Rename SampleIntegrationApplicationTests
Merge branch '1.1.x'