XD-193: Moved all context files to some subdir of META-INF/spring-xd
XD-202: Change twittersearch to use bearer token

Uses an OAuth2Template to perform client-credentials OAuth2 grant
using the consumerKey and consumerSecret as client_id and client_secret.

The TwitterTemplate is then created internall using the bearer token
from the grant.

This reduces the number of parameters required to configure the module.
Update Spring Social Twitter to 1.0.5
XD-207 added config/hadoop.properties
Generate API Docs
XD-217 Add config dir to classpath 

Support custom properties files for the properties-location
attribute of transform, filter, script modules
INT-219 suppress WARNING messages in local mode
INT-219 fixed RedisChannelRegistryTests, null channel handlers no longer tracked for clean up
Add cleanDist task to delete $rootDir/dist before running distXD