Accept callback for formatting tokens

[1ec5]

Added a formatToken option to compile, getWayName, and tokenize that gives the client an opportunity to manipulate a road name or other token value after any transformations built into this library but before the value is inserted into the overall instruction string. This feature is based on a similar feature built into the Swift version of this library.

Serving suggestion:

var instruction = osrmTextInstructions.compile(language, step, {
  formatToken: function (token, value) {
    // Mark up numbers to be pronounced like numbers in addresses.
    value = value.replace(/\w*[\d.-]+\w*/g, `<say-as interpret-as="address">${value}</say-as>`);
    // Wrap road names in their pronunciations, if available.
    switch (token) {
      case 'name': case 'way_name':
        return step.pronunciation ? `<phoneme ph="${step.pronunciation}">${value}</phoneme>` : value;
      case 'rotary_name':
        return step.rotary_pronunciation ? `<phoneme ph="${step.rotary_pronunciation}">${value}</phoneme>` : nil;
      default:
        return value;
    }
  }
});

Fixes #52.

/cc @mcwhittemore @allierowan @bsudekum

[1ec5]

This feature enables a superset of the use cases addressed by the tokenizedInstruction hook that was added in #79, although this feature is a little more verbose. Should we remove tokenizedInstruction?

[yuryleb]

Wow, non-capturing group 👍

[mcwhittemore]

@1ec5 - I think this is a big step up on tokenizedInstruction and I agree we should drop that.

Lets merge and roll.

[1ec5]

7903e28 removes tokenizedInstruction and indeed the entire options parameter to the module (to avoid warnings about unused variables).