fix for: (if thread is not found then just display the detail string)

Exception in thread "Text Viewer Hover Presenter"
java.lang.StackOverflowError
at
org.eclipse.ui.internal.WorkbenchWindow.getActivePage(WorkbenchWindow.java:1461)
at
org.eclipse.dltk.internal.debug.ui.ScriptEvaluationContextManager.getEvaluationContext(ScriptEvaluationContextManager.java:201)
at
org.eclipse.dltk.internal.debug.ui.ScriptEvaluationContextManager.getEvaluationContext(ScriptEvaluationContextManager.java:196)
at
org.eclipse.dltk.debug.ui.ScriptDebugModelPresentation.getEvaluationThread(ScriptDebugModelPresentation.java:121)
at
org.eclipse.dltk.debug.ui.ScriptDebugModelPresentation.computeDetail(ScriptDebugModelPresentation.java:609)
at
org.eclipse.dltk.debug.ui.ScriptDebugModelPresentation.getVariableDetail(ScriptDebugModelPresentation.java:436)
at
org.eclipse.dltk.debug.ui.ScriptDebugModelPresentation.getValueText(ScriptDebugModelPresentation.java:420)
at
org.eclipse.dltk.debug.ui.ScriptDebugModelPresentation.computeDetail(ScriptDebugModelPresentation.java:612)
at
org.eclipse.dltk.debug.ui.ScriptDebugModelPresentation.getVariableDetail(ScriptDebugModelPresentation.java:436)
at
org.eclipse.dltk.debug.ui.ScriptDebugModelPresentation.getValueText(ScriptDebugModelPresentation.java:420)
at
org.eclipse.dltk.debug.ui.ScriptDebugModelPresentation.computeDetail(ScriptDebugModelPresentation.java:612)
at
org.eclipse.dltk.debug.ui.ScriptDebugModelPresentation.getVariableDetail(ScriptDebugModelPresentation.java:436)
Merge branch 'master' into TypeLibs
validation if type libary not found