Added multiple changes required to use 4 separate input unigram thesauri (one per PoS) as source for n-gram thesauri
Refactored things a bit so that the two-step thesaurus building process still works even if we do not mess with the vectors inbetween the two stages
Added support for either Byblo precomputed thesauri or vectors (which this program will compose itself), configurable via conf['vector_sources']['precomputed']
Added support for preserving the original early-stage thesaurus files (events, entries and features) when building an ngram-augmented thesaurus
moved a function, added a logging statement