Add support for nxxm.

[nxxm](https://nxxm.github.io)

src/ftxui/dom/text.cpp

@@ -0,0 +1,37 @@
+#include "ftxui/dom/node.hpp"
+
+namespace ftxui {
+
+using ftxui::Screen;
+
+class Text : public Node {
+ public:
+  Text(std::wstring text) : Node(), text_(text) {}
+  ~Text() {}
+
+  void ComputeRequirement() override {
+    requirement_.min.x = text_.size();
+    requirement_.min.y = 1;
+  }
+
+  void Render(Screen& screen) override {
+    int x = box_.x_min;
+    int y = box_.y_min;
+    if (y > box_.y_max)
+      return;
+    for (wchar_t c : text_) {
+      if (x > box_.x_max)
+        return;
+      screen.at(x++, y) = c;
+    }
+  }
+
+ private:
+  std::wstring text_;
+};
+
+std::unique_ptr<Node> text(std::wstring text) {
+  return std::make_unique<Text>(text);
+}
+
+};  // namespace ftxui