List of index functions

The following is a list of all functions that appear in the mastertable, along with the implementations in climix. At the moment, of course, most implementations are missing. @a001257 could you prioritize the remaining ones? Or perhaps in some cases comment on their necessity?

mastertable	climix implementation
FUN_count	count_occurrences
FUN_csdi
FUN_dd
FUN_dtr
FUN_frac
FUN_growing
FUN_max
FUN_mean
FUN_min
FUN_prctile
FUN_spell	spell_length
FUN_wsdi