forked from GitHub/gf-core
Profiling the compilation of the OALD lexicon showed that 90-95% of the time was spent in topoSort. The old implementation was quadratic. Replaced this with O(E + V) implementation, in GF.Data.Relation. This gave a 10x speed-up (~ 25 sec instead of ~270 sec) for compiling ParseEng and OaldEng.