Fix radiasoft/sirepoflash#8. Move useHeatExchange to advanced.
Fix radiasoft/sirepoflash#8. Move useHeatExchange to advanced.

radiasoft/sirepo,mkeilman/sirepo,mkeilman/sirepo,radiasoft/sirepo,mkeilman/sirepo,mkeilman/sirepo,radiasoft/sirepo,radiasoft/sirepo,radiasoft/sirepo