Add flow type checking

Gulpfile.js

@@ -3,17 +3,10 @@
 'use strict';
 var _ = require('lodash');
 var gulp = require('gulp');
-var gutil = require('gulp-util');
-var watch = require('gulp-watch');
-var plumber = require('gulp-plumber');
-var filelog = require('gulp-filelog');
-var cleanDest = require('gulp-clean-dest');
 var uglify = require('gulp-uglify');
 var rename = require('gulp-rename');
 var webpack = require('webpack');
 var bump = require('gulp-bump');
-var react = require('gulp-react');
-var flow = require('gulp-flowtype');
 var argv = require('yargs').argv;
 
 var pkg = require('./package.json');
@@ -39,10 +32,6 @@ function webpackConfig(extension, overrides) {
   return _.assign({}, defaults, overrides);
 }
 
-function logPluginError(error) {
-  gutil.log(error.toString());
-}
-
 gulp.task('build', function(callback) {
   webpack(webpackConfig('.js'), callback);
 });
@@ -118,25 +107,6 @@ gulp.task('watch', function() {
   gulp.watch('src/*', ['build-debug']);
 });
 
-// To use this, each javascript file must have /* @flow */ on the first line
-gulp.task('typecheck', function() {
-  return gulp.src('src/*.js')
-  .pipe(flow({      // note: do not set the 'all' option, it is broken
-    weak: true,   // remove this after all errors are addressed
-    killFlow: true
-  }));
-});
-
-gulp.task('strip', function() {
-  return gulp.src('src/*.js')
-  .pipe(watch('src/*.js'))
-  .pipe(cleanDest('out'))   // delete outdated output file before stripping
-  .pipe(plumber())        // prevent an error in one file from ending build
-  .pipe(react({stripTypes: true}).on('error', logPluginError))
-  .pipe(filelog())
-  .pipe(gulp.dest('out'));
-});
-
 gulp.task('version-bump', function() {
   if (!argv.type) {
     throw new Error('No type found, pass it in using the --type argument');