When Logback is the logging system, ensure that JBoss logging uses it

Previously, if Logback was being used as Boot's logging system, but
Log4J was also on the classpath before SLF4J and Logback, JBoss
Logging would use Log4J for its logging. This lead to warning messages
being produced as Log4J was not configured:

log4j:WARN No appenders could be found for logger (org.jboss.logging).
log4j:WARN Please initialize the log4j system properly.

This commit updates LogbackLoggingSystem to set the
org.jboss.logging.provider to "slf4j". This ensure that JBoss Logging
will use SLF4J and Logback as intended even when Log4J is also on the
classpath.

Closes gh-1928
Merge branch '1.1.x'

Conflicts:
	spring-boot/src/main/java/org/springframework/boot/logging/logback/LogbackLoggingSystem.java
	spring-boot/src/test/java/org/springframework/boot/logging/logback/LogbackLoggingSystemTests.java
Ensure java.io.tmpdir is available before using it

Some environments do not have a tmpdir so it can be null.
Minor fixes in howto documentation re:SSL config

Fixes a couple of typos in the documentation:
* `x-forwarded-protocol` is not the standard name for this header
* `require_https` is not an existing property, but rather `require_ssl`
Be defensive about classloader in MessageSourceAutoConfiguration

Fixes gh-1960
Merge branch '1.1.x'
Fix manual metadata format inconsistency

Fixes gh-1961
Disable check of Groovy template location by default for CLI apps

In 1.1, the Groovy template support did not check that its configured
template location exists. A check was added in 1.2, however this
breaks CLI web applications that don't have the expected templates
location.

Rather than reintroducing 1.1's behaviour by removing the check, this
commit updates the CLI to set
spring.groovy.template.check-template-location to false by default.
This allows flow-blown applications to benefit from the check, while
allowing CLI apps to behave as they did in 1.1.

Closes gh-1959
fix copy in README
Merge pull request #1963 from mikfreedman/master

* pull1963:
  fix copy in README
  Disable check of Groovy template location by default for CLI apps
Add documentation for the deprecated field
Add GsonJsonParser
Remove unecessary Jackson dependency in trace filter
Fix copy in README

(cherry picked from commit d4bf221f)
Merge branch '1.1.x'
Clarify configuration meta-data details

Update the configuration meta-data appendix to clarify a few things.
Polish
Add SqlScriptsTestExecutionListener

Update @IntegrationTest to include SqlScriptsTestExecutionListener.

Fixes gh-1965
Improve MongoDataAutoConfiguration

Update MongoDataAutoConfiguration to provide easier configuration of
CustomConversions, the MappingMongoConverter, MongoMappingContext
and an authentication database.

Fixes gh-1619
Fixes gh-1730
Rename spring.data.mongo.repositories.enabled

Rename mongo to mongodb.

Fixes gh-1966