Add hideConsole()

• glfw.hideConsole() - Windows ONLY hides the console window, but only in case
  this console window is property of this process. For instance this works if you use
  pkg module to bundle your app, and then doubleclick the EXE. But if you are running
  a command like node script.js, then this won't hide the window. It's safe to call
  this function on all platforms, but it will be ignored, unless the platform is Windows.

• glfw.showConsole() - Windows ONLY shows the console window
  if it was previously hidden with glfw.hideConsole().

• The README was expanded with all the exports of glfw.

• There are slight (and still wip) optimizations in mousemove event dispatching.