Fix tag URL is [object object] & Add some updates

[cool4zbl]

Hi there, I've used this tool to build my Ghost blog, and it was so cool!
However, I found there were somewhere I was not so satisfied and even found a small bug of generating the tag URL, so I made some updates and fix the bug.

• Fix tag URL is [object object]
• Beautify the post URLs in the index page.
  E.g. {hostname}/2017-07-02-welcome-to-ghost.html -> {hostname}/2017-07-02-welcome-to-ghost/.
  E.g. {hostname}/2017-07-02-welcome-to-ghost/index.html -> {hostname}/2017-07-02-welcome-to-ghost/
• Use colors package for debugging easily.

@mixu
Please review, thanks! 😃

[autonome]

I just started looking into [object Object] bug today but decided to check here first. Glad I did, thanks for the patch!

[cool4zbl]

@autonome Glad to help you. 😄

[autonome]

Hi @mixu, are you interested in giving us commit access? Or if you do no plan to accept any PRs, do you recommend we fork active dev to a new repo?

THanks!