soere: ParametersWidget does not allow direct filtering on methods or units

[Olivier Maury]

The selector ParametersWidget is used at:
- soerepro/insertion/dataTemplate
- soeretypo/insertion/composition_template

The selection is:
1/ Parameter type
2/ Parameter
3/ Method or unit

Moreover search is available on the presented results.

On 1st March 2012, Aurelia wants to filter on method or unit without choosing a parameter.

So updates on this widget must be:
1/ change on one of the dropdown list,
2/ request with all values of the dropdown lists and the changed list id,
3/ response with values for filling all the dropdown lists and the main widget
4/ filling the dropdown list, filling the main widget and clearing the search box