Replace async.js with Promise

[abetomo]

Since Promise is now available as a standard, I would like to replace async.js with Promise.
In addition, I want to improve nested deep callback.

What do you think?

[DeviaVir]

+1 on using promise

[abetomo]

Since async.js is no longer used, close it.
Separately, I think that we will reduce callback and make it a chain of Promise.