Also a minor speedup for setting model dimension (set `msft` etc.)

Uses new set `fts(f, t, s)` which is the same as `sft` but different order of domains.

Also enables the use of scenario tree construction with SCENRED2

Default is zero, can be changed via command line parameter --debug=[0|1|2].

Also minor edits to smoothing calculation

Writes srin.gdx to and reads srout.gdx from the root dir

Activate this feature using active('scenRed') and setting mSettings parameters 'red_num_leaves' or 'red_percentage'.