Assorted upstream changes

Several different changes.

Ola, can you please have a look at my last commit

1) 
I need to add a new property to DQuestion.
A list of questions this question depends on. The idea is that a question should only be enabled if its dependant questions have been filled in.
E.g. The "quantity" question should only be enabled when the "product" questions have been filled in.

What is the best property to use for this (right now it is a Collection<Long>)?

2)
We need to add a REST method that return a list of all responses for a certain extMeetingId.
I added
/api/{domain}/survey/v10/response?extMeetingId=123
to the Survey controller.
Today the app needs to send one request for each survey/version combination to figure out if there is a response.

I am not able to add the method to the Response controller due to how that controller is mapped. 
Can I do like this?

/Mattias