XD-1472  Allow modules to define a default inputType

XD-1472 minor change to FlattenedCompositeModuleOptionsMetadata

XD-1472 added comment to repositories.xml
XD-1629/1653 RabbitMessageBus Enhancements

- Add retry options (back off etc)
- Add Recoverer so failed messages can be routed to a DLQ
- Add prefix to queues/exhanges for configuring HA/DLE via policy

XD-1629 Polishing; Mapped Headers

- add commented props to servers.yml
- add support for mapped headers, with default map all
XD-1446 Update spring-data-hadoop dependency and add new Hadoop distros

- Changing Spring for Apache Hadoop dependency to 2.0.0.RC3

- Adding Pivotal HD 2.0 as distro (phd20)

- Adding Cloudera CDH5 as distro (cdh5)

- Changing Hortonworks Data Platform version 2.0 to 2.1 (hdp21)
XD-1677 Add 'level' and 'expression' to Log Sink

JIRA: https://jira.spring.io/browse/XD-1677

Use `--expression=#root` to log entire message.

Polishing

Offline comments...

 - change default level to INFO
 - add 'xd.sink' as the log category prefix
 - set the xd.sink log category level to INFO
XD-1281 Create Better UI instead of Boot's default "Whitelabel Error Page"

* Add static 404 page modeled after spring.io
* Add ErrorHandler, extending `org.springframework.boot.actuate.web.BasicErrorController`
  - redirect 404 statuses to static page
Fix compiler error on using java 1.6