Better management of 'reCompute'

We use config['deletenonvalues'] : default is 1 : we delete the value for 'not relevant question'

Default is:

- No Update in url
    - submitted or unsubmitted survey : recompute=1 relevance from config
- Update in url
    - submitted survey : recompute=1 and relevance=config['deletenonvalues']
    - submitted survey : recompute=1 and relevance=config['deletenonvalues']
- recompute=1 in url
    - Allways recompute
- relavance=1 in url
    - Allways relevance

For equation question type : if recompute : allways use relevance