LREngine bugfix for checkboxes.java

// add these properties to the RollupSummaryField class.
public boolean isMasterTypeCheckbox;
public boolean isDetailTypeCheckbox;

// add these to LREngine RollupSummaryField class constructor (starts at line 420)
this.isMasterTypeCheckbox = isCheckbox(master.getType());
this.isDetailTypeCheckbox = isCheckbox(detail.getType());

// Add this anywhere inside RollupSummaryField inner class
boolean isCheckbox (Schema.Displaytype dt) {
    return dt == Schema.DisplayType.Boolean;
}

//this should replace the current line 320
        for(Id masterRecId : masterIds)
            for (RollupSummaryField rsf : ctx.fieldsToRoll)
                masterRecordsMap.get(masterRecId).put(rsf.master.getName(), 
                    rsf.isMasterTypeNumber ? 0 : (rsf.isMasterTypeCheckbox ? false,null));