Add more examples.

examples/dom/blink.cpp

@@ -0,0 +1,21 @@
+#include "ftxui/screen.hpp"
+#include "ftxui/dom/elements.hpp"
+#include <iostream>
+
+int main(int argc, const char *argv[])
+{
+  using namespace ftxui;
+  using namespace ftxui::dom;
+  auto document =
+    hbox(
+      text(L"This text is "),
+      text(L"blink") | blink,
+      text(L". Do you like it?")
+    );
+  auto screen = ftxui::Screen::TerminalOutput(document);
+  Render(screen, document.get());
+
+  std::cout << screen.ToString();
+
+  return 0;
+}