This moves the remaining bits of NSApplication initialization into
_glfwPlatformInit. As a side-effect of this, any command-line program
initializing GLFW will get a menu bar, which is not ideal.
If this has happened to you and a bisect led you here, please see the
GLFW_COCOA_MENUBAR init hint introduced in GLFW 3.3.
If this patch is a terrible idea, please get in touch in the 3.4 release
timeframe.
This is a replacement for 6e6805000a,
which attempts to preserve the existing menu bar creation behavior for
the 3.3-stable branch.
Fixes#1649.