Fixed broken key repeat detection.
Fixed glfwShowWindow restoring maximized windows.

Fixes #264.
Added GLFW_ICONIFY_DEFOCUSED.

By default, full screen windows that lose focus will be iconified and
the video mode will be restored.  This makes it impossible to create
applications spanning multiple monitors.  The GLFW_ICONIFY_DEFOCUSED
window hint will allow users to disable this behavior.

Fixes #143.
Removed tautological test.
Made glfwGetCursorPos query system directly.

Fixes #103.
Aligned Win32 cursor pos path with X11 path.
Consume WM_ERASEBKGND.
Added GLFW_DONT_CARE.

This changes the behavior of framebuffer hints set to zero.  Before,
zero meant that any value was acceptable.  This changes zero to be an
explicit preference and adds GLFW_DONT_CARE to mean that any value is
equally acceptable.

Fixes #70.
Added GLFW_DOUBLEBUFFER.
Added glfwGetKeyName.
Added glfwSetSizeLimits.
Added position testing to windows test.
Updated glad.
Fixed plural forms on key/button arrays.
Made windows test show all windows at once.
Formatting.
Documentation work.