Added getSurveyForContent method to SurveyLogic.
This method returns a Survey for a given content. The backreferenceproperty will not work because of inheritance.
"""
Code used in a couple of places to work with the current thread's environment.
Current users include i18n and request prefix handling.
"""
try:
import threading
currentThread = threading.currentThread
except ImportError:
def currentThread():
return "no threading"