Add option to override log output?

[ansballard]

Wondering if anyone else would be interested in an option to override the log function at https://github.com/klei/gulp-inject/blob/master/src/inject/index.js#L107. The quiet option is nice, but I'm wrapping gulp and doing all the logging myself. It would be nice to be able to pass in a function like

function log(filesCount, target) { console.log(`${customPrefix()} ${filesCount} injected at ${target.path}`);

so I can keep my output consistent without sacrificing useful runtime info.

Figured I'd add in how to go about implementing since it's a pretty small change.

// ...
function getNewContent(target, collection, opt) {
  /* Assign from opt or default to the old functionality */
  var logger = opt.log || (opt.quiet ? noop : function (filesCount) {
    if (filesCount) {
      log(cyan(filesCount) + ' files into ' + magenta(target.relative) + '.');
    } else {
      log('Nothing to inject into ' + magenta(target.relative) + '.');
    }
  });
// ...