The main command becomes a subcommand named "run", which starts a "compl" server.
Create "build" subcommand.
"InflateArpaModel" converts an ARPA-formatted model into a model for compl.
Inflate models from io.Reader.
"Build" subcommand deserializes a model from an ARPA file and serialize it as a binary file.
Merge branch 'feature/build-subcommand'