with benchmarks/space/Space size of key checked and the strict list of keys in Base module optimized

by introducing list nodes with 2 or 3 chars stored in.
With this optimization the overall number of cells required is
reduced by 25%.
Benchmark statistics for this step by step optimizations
are stored in the *.stat files
in Data.StringMap.Base new lookup functions lookupGE, lookupLE, lookupRange for range search