Get the N-gram order from the command-line arguments.
"(*Predictor).Order" returns the N-gram order, which is used for the window size of context.
Separate handlers from "server.go".
Rename "handler" to "getCandidates".
Add an endpoint to get the N-gram order. It is used to decide the window size of context.
Merge branch 'feature/build-command-ngram-order'