A library paring TLA+ language. Gem name `tla-parser-s` because did not want to reserve "officical" `tla-parser` name. Sematic routines create a list of files -names (=modules) needed to satisfy set of entry points. Entry points include names passed as parameters to command line tool (`bin/tla-resolver.rb`), or as API paramters to `TlaParserS::Resolver#resolveModulesDo`.