Refactor of template and script services to allow easy addition of further template and script processors.

Hightlights of check-in include:
- Introduction of script processor 
- Neutralisation of script and template models
- The notion of a processor extension introduced
- Extensions applied to processor implementation rather than the services
- Auto selection of processor based on file extension of template or script

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@5519 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/web/forms/RenderingEngineTemplateImpl.java

@@ -223,7 +223,7 @@ public class RenderingEngineTemplateImpl
       String result = null;
       try
       {
-         result = templateService.processTemplateString(null, 
+         result = templateService.processTemplateString("freemarker", 
                                                         outputPathPattern,
                                                         new SimpleHash(root));
       }