New function to set a given parameter property's value.  This makes it much easier to setup an initial parameter list (with name, type etc.), & then to update a given parameter's value property, say, at runtime.

Also, the dialog will now construct each parameter's control dependent on its type property; text = textbox, select = select listbox, multiselect = select listbox with the 'multiple' attribute set, checkbox = checkbox, & radio = radiobutton.  For array controls (select, multiselect, & radio), the parameter's 'entries' array must be set.  Each element of this array is of the form: {value: "", label: ""}, where value is what's returned from a call to getParameterList(), & label is what's shown to the user in the dialog.
Minor mod. to WPS.Dialog example page.  It now demonstrates usage of different dialog control types (a select listbox), for the year parameter.