Define the following types:
    struct xegl_config
    struct xegl_context
    struct xegl_display
    struct xegl_platform
    struct xegl_window

Implement the following functions, which includes all entries in the
native dispatch table:
    xegl_config_choose
    xegl_config_destroy
    xegl_context_create
    xegl_context_destroy
    xegl_display_connect
    xegl_display_disconnect
    xegl_dlsym_gl
    xegl_get_proc_address
    xegl_make_current
    xegl_platform_create
    xegl_platform_destroy
    xegl_window_create
    xegl_window_destroy
    xegl_window_swap_buffers

Signed-off-by: Chad Versace <chad.versace@linux.intel.com>