Further separation of window and context.

The context related parts of _GLFWwndconfig have been moved to
_GLFWctxconfig and given better names.  Window hint and attribute
members have been renamed to match.

src/glx_platform.h

@@ -124,7 +124,7 @@ typedef struct _GLFWlibraryGLX
 int _glfwInitContextAPI(void);
 void _glfwTerminateContextAPI(void);
 int _glfwCreateContext(_GLFWwindow* window,
-                       const _GLFWwndconfig* wndconfig,
+                       const _GLFWctxconfig* ctxconfig,
                        const _GLFWfbconfig* fbconfig);
 void _glfwDestroyContext(_GLFWwindow* window);