Fix gulp tasks

[steven-pribilinskiy]

@brianpkelley Additional refactoring was required because of broken livereload functionality and to get rid of commented piped plugins. Being a "webpack-guy" I've removed the run-sequence plugin that was necessary for running tasks in proper sequence.

run-sequence is a temporary solution until gulp will support such functionality natively in v4. Btw, it's almost ready! https://github.com/gulpjs/gulp/milestone/1

Notes:

• the commented piped plugins was intended for production builds and gh-pages, so I've introduced the env object with prod property and a new gulp task build:production to handle these.

• I've removed demo-resources and dist-resources tasks, they are probably related to 0.x demo

• source maps doesn't work yet (the build:production task)

• the duplicate minified files in dev environment are still required, because they are referenced in the demo index file. I see several solutions here:

  • reference non-minified files
  • find-replace .min. to . in the index.html before serving it in server:demo task
  • use webpack for builds and webpack-dev-server for live reload, for me it's a task runner with hot reloading of changes which allows you to forget about all JS/CSS watchers