Fix search mode display of fields, and also fix id/for attributes of boolean in forms

This patch actually based on 1.9.x fix the following issues (list in the same order than the patch):

• In search mode, an additionnal argument may be given to list field to precise if single or multiple selection is allowed, default is multi-select, and therefore Backward compatibility is ensured.
• In search mode, list display are filtered to only display values that pass validation, (removing the values "not specified" for mandatory fields), which avoid useless empty results
• In search mode, only small list (less than 6 items) may be displayed as radio/checkbox button, default is to display a select/list box
• In search mode, radio displayed list are displayed as checkbox for multi-select and radio for single select
• In search mode, drop-down list are extended to 5 item lists for multi-select
• the makeQuery function of list is now functionnal, and lessthan/greaterthan prefix is also supported for list
• boolean fields select/checkbox/radio display has proper id/for attributes for accessibility
• In search mode, only radio display is supported for boolean, and is now functional, including three-state mode
• the makeQuery function of boolean is now functionnal

I know this patch is a little bit large and that it fix an almost deprecated search mode, but it make it functional, and we use it sucessfully since a while now. I have taken some arbitrary options, but I feel this is not in a sensible part of the product. I provide this patch as is, to helps, I completely understand if you dislike it.