replace arguments by hack to add empty params.filters to request for buildUrl

Fixed TwitterProxy

/**
     * We need to add a little processing to the normal buildRequest. In YQL we send an SQL-like
     * query statement - in this case using the search query above. To honor the filters applied 
     * by the user, we pull those out in this function and apply them to the search XTemplate.
     * Finally, we modify the url to add this generated query and any other required parameters.
     */
    buildRequest: function(operation) {
	var hack = Ext.apply({params: {filters: []}}, arguments);
        var request    = Ext.data.KivaProxy.superclass.buildRequest.apply(this, [hack]),
            queryTpl   = this.queries.search,
            filters    = operation.filters || [],
            filterData = {};
        
        Ext.iterate(filters, function(filter) {
            filterData[filter.property] = filter.value;
        });
        
        delete request.params.filters;
        
        Ext.applyIf(request.params, {
            format: 'json',
            q: queryTpl.applyTemplate(filterData)
        });
        
        request.url = Ext.urlAppend(request.url, Ext.urlEncode(request.params));
        
        return request;
    }