Modified EntityHub API breaks Refactor enhancement engine

A change in the EntityHub services API is causing the refactor enhancement engine not to compile anymore. The Sign interface and related classes/methods seem to be gone (not deprecated).

Note: the reasoners.base.api package error is an unused import, statement can be removed.

I'm not marking this bug as Critical or Blocker due to the refactor engine not being brought in by any reactor POM.

[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] /Users/alessandro/workspaces/IKS/stanbol-new/enhancer/engines/refactor/src/main/java/org/apache/stanbol/enhancer/engines/refactor/RefactorEnhancementEngine.java:[33,53] cannot find symbol
symbol : class Sign
location: package org.apache.stanbol.entityhub.servicesapi.model

[ERROR] /Users/alessandro/workspaces/IKS/stanbol-new/enhancer/engines/refactor/src/main/java/org/apache/stanbol/enhancer/engines/refactor/RefactorEnhancementEngine.java:[47,44] package org.apache.stanbol.reasoners.base.api does not exist

[ERROR] /Users/alessandro/workspaces/IKS/stanbol-new/enhancer/engines/refactor/src/main/java/org/apache/stanbol/enhancer/engines/refactor/RefactorEnhancementEngine.java:[703,2] cannot find symbol
symbol : class Sign
location: class org.apache.stanbol.enhancer.engines.refactor.RefactorEnhancementEngine

[ERROR] /Users/alessandro/workspaces/IKS/stanbol-new/enhancer/engines/refactor/src/main/java/org/apache/stanbol/enhancer/engines/refactor/RefactorEnhancementEngine.java:[703,41] cannot find symbol
symbol : method getSign(java.lang.String)
location: interface org.apache.stanbol.entityhub.servicesapi.site.ReferencedSiteManager

[INFO] 4 errors
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[ERROR] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Compilation failure