add sublime-gulp cache

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>
Export gulp from your gulpfile.js by adding module.exports = gulp; for gulp-devtools

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>
add Gulp in Chrome Devtools doc.

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>