Fix doc tests in older Rust versions
//! # extern crate imgui_glutin_support;
//! use imgui::ImGui;
//!
+//! # fn main() {
//! let mut imgui = ImGui::init();
//! imgui_glutin_support::configure_keys(&mut imgui);
+//! # }
//! ```
//!
//! In your main loop you should already be retrieving events from glutin and handling them. All
//! # extern crate imgui_glutin_support;
//! # use glutin::EventsLoop;
//! # use imgui::ImGui;
+//! # fn main() {
//! # let mut events_loop = EventsLoop::new();
//! # let mut imgui = ImGui::init();
//! events_loop.poll_events(|event| {
//!
//! imgui_glutin_support::handle_event(&mut imgui, &event);
//! });
+//! # }
//! ```
//!
//! # Advanced use cases
//! # extern crate imgui_glutin_support;
//! # use glutin::{EventsLoop, Event, WindowEvent, MouseScrollDelta, TouchPhase};
//! # use imgui::ImGui;
+//! # fn main() {
//! # let mut events_loop = EventsLoop::new();
//! # let mut imgui = ImGui::init();
//! events_loop.poll_events(|event| {
//! }
//! }
//! });
+//! # }
//! ```
extern crate glutin;
