Unicode simple casefolding functions generator.

Rationale: sometimes we need to perform locale-independent case insensitive string comparesion,
but icu may seems too heavy. For this purpose this generator is written.

It produces body of pure C functions that takes unsigned int "c" argument and returns
approproate simple casefolding according to supplied CaseFolding.txt data file.
This function is constructed from balanced binary tree with some optimizations that allowed
to reduce data size to less than 4 kilobytes, saving cache for other important things.

You can play around with parameters for cf:
  -c NUM   maximum number of characters between discontiguous intervals to reduce height of the
           tree and total number of branches
  -d (-D)  (dis)allow "delta" mapping where value of resulting character calculated as "c + delta"
  -s (-S)  (dis)allow "set" mapping where value of resulting characted calculated as "c | 1"
  -x (-X)  (dis)allow interval analysis to detect intervals where almost all characters but few
           may be produced as "c + delta" and use translation tables for rest characters
  -y (-Y)  (dis)allow interval analysis to detect intervals where almost all characters but few
           may be produced as "c | 1" and use translation tables for rest characters

Resulting code is printed to stdout with some comments: tree height, total size of translation tables
and number of branches.