new Buffer is deprecated and unsafe

[ghost]

What does it do?

new Buffer -> Buffer.from or Buffer.alloc.
We should not use Buffer constructor which is deprecated and unsafe.

Any helpful background information?

The behavior of new Buffer() is different depending on the type of the first argument, security and reliability issues can be inadvertently introduced into applications when argument validation or Buffer initialization is not performed.

To make the creation of Buffer instances more reliable and less error-prone, the various forms of the new Buffer() constructor have been deprecated and replaced by separate Buffer.from(), Buffer.alloc(), and Buffer.allocUnsafe() methods.

Check this out:

• https://nodejs.org/api/buffer.html#buffer_buffer_from_buffer_alloc_and_buffer_allocunsafe

What else?

This PR failed CI test on Node.js 0.10, 0.12. However, those versions are no longer supported.

• https://github.com/nodejs/Release#end-of-life-releases