Reduce CDO repeated warnings

CDORemapper() uses s2dv::CDORemap, which usually returns several warning messages. For example,

Warning (cdfInqContents): Coordinates variable time can't be assigned!
Warning (cdfInqContents): Coordinates variable height can't be assigned!
5: In (function (data_array = NULL, lons, lats, grid, method, avoid_writes = TRUE,  :
  CDORemap: Using CDO version 1.9.8.

It is bearable when using s2dv::CDORemap standalone since the warnings show once only. However, since Start() calls CDORemapper() several times, and Start() can load numerous files, the warnings are duplicated and overwhelm the screen. It would be more user-friendly to reduce repeated warning messages or provide an option to hide all the warnings.