Added CFU_MODE(), CFU_DTF(), CFU_DTO() and CFU_EOF() to CFU_Rfunc library.

These functions detrend observed (CFU_DTO) and forecast (CFU_FTO) anomalies of, e.g., North Pacific (PDO) SSTs,
then compute the observed EOF mode (CFU_EOF) and project the anomalies onto the observed EOF pattern CFU_MODE().

Find an example below.

Detrend obs anomalies:
tmp2 <- CFU_DTO(lons,lats,XY1_ano_obs)

EOF of detrended obs anomalies::
tmp3 <- CFU_EOF(lons,lats,tmp2$ano.dt)

Detrend forecast anomalies:
tmp4 <- CFU_DTF(lons,lats,XY1_ano_exp,exp_gmt_an)

Obs PCs:
tmp11 <- CFU_MODE(lons,lats,XY1_ano_obs,tmp3,mode=1)
Forecast PCs:
tmp12 <- CFU_MODE(lons,lats,XY1_ano_exp,tmp3,mode=1)