CST_Subset(): Fix bug that caused incorrect subsetting of coordinate values when only subsetting along one dimension

Hi @erifarov,

While doing some tests for CST_SaveExp() I found this bug in CST_Subset:

library(CSTools)
exp <- CSTools::lonlat_prec_st
exp_subset <- CST_Subset(exp, along = "ftime", indices = 1:3, drop = F)
exp_subset$dims
# dataset     var  member   sdate   ftime     lat     lon 
#       1       1       6       3       3       4       4 
exp_subset$coords$ftime
# [1] 1
# attr(,"indices")
# [1] TRUE

As you can see, $coords$ftime should have values 1, 2, 3 but instead only had one. After investigating a little bit I found out that is is because at line 90: index <- indices[[dimension]] index becomes unlisted due to the use of [[ and then .subset_with_attrs() only retrieves the first value of the array.

I have fixed this by changing the line to index <- indices[dimension] so that index remains a list with only the element dimension. Please let me know if you have any questions or if you think there is any problem with this fix.

Thanks,

Victòria