XD-561 Parse now verifies that all modules are valid.

XD-561 Tests now support enhanced parser

Merged code after rebase.

Added changes requested from code review.

EnhancedParser now checks for nulls in its constructors.

Code Meets Code Review requests.
Updated code based on code review comments

Removed the toLowerCase for the name string for name searches.

Bug fix for a module that is both source and sink.
Pass messages that are already JSON thru
XD-561 - added resource.exists() check in ModuleRegistry.loadResource() implementations
XD-678 -renamed accepted-media-types to accepted-content-types
Merge branch 'XD-675' of git://github.com/ericbottard/spring-xd into ericbottard-XD-675
Introduce NamedResource and provide tab completion for existing entities
Make moduleRegistry available to xd-admin

xd-admin is currently unable to start due to missing
moduleRegistry bean.
Fix FileModuleRegistry not loading modules

FileModuleRegistry is using the module directory
name in all caps, which doesn't work on a case-sensitive
OS