update require/import section of javascript.md

[kevinbarabash]

• remove sorting of require/import statements
• blocks continues to be the same with the addition of a new block, flow type imports which should come last
• prefer ES6 import syntax over require
• destructuring should happen on the same line as the import, e.g. import React, {Component} from 'react'

[jlfwong]

:o did someone update kake to compile ES6 syntax?

[xymostech]

@jlfwong I believe it always did, but the require-finding regexes got confused. :) @jeresig fixed that!

[jlfwong]

Yeah, that's what I meant :) Glad to hear the artificial restriction to the code I wrote long ago isn't holding anyone back :D