Enable raw keyboard input (#832)

In order for applications to receive all keyboard inputs, including the
Ctrl-C and Ctrl-Z, the raw input mode has been enabled. As result the
SIGINT will no longer be used, instead the keyboard Ctrl-C event is used
for exiting the framework, but only if no components has made use of it.

Co-authored-by: Jørn Gustav Larsen <jgl@fasttracksoftware.com>
Co-authored-by: ArthurSonzogni <sonzogniarthur@gmail.com>

src/ftxui/component/screen_interactive_test.cpp

@@ -64,4 +64,71 @@ TEST(ScreenInteractive, PostTaskToNonActive) {
   screen.Post([] {});
 }
 
+TEST(ScreenInteractive, CtrlC) {
+  auto screen = ScreenInteractive::FitComponent();
+  bool called = false;
+  auto component = Renderer([&] {
+    if (!called) {
+      called = true;
+      screen.PostEvent(Event::CtrlC);
+    }
+    return text("");
+  });
+  screen.Loop(component);
+}
+
+TEST(ScreenInteractive, CtrlC_Forced) {
+  auto screen = ScreenInteractive::FitComponent();
+  screen.ForceHandleCtrlC(true);
+  auto component = Renderer([&] {
+    screen.PostEvent(Event::CtrlC);
+    return text("");
+  });
+
+  int ctrl_c_count = 0;
+  component |= CatchEvent([&](Event event) {
+    if (event != Event::CtrlC) {
+      return false;
+    }
+
+    ++ctrl_c_count;
+
+    if (ctrl_c_count == 100) {
+      return false;
+    }
+
+    return true;
+  });
+  screen.Loop(component);
+
+  ASSERT_LE(ctrl_c_count, 50);
+}
+
+TEST(ScreenInteractive, CtrlC_NotForced) {
+  auto screen = ScreenInteractive::FitComponent();
+  screen.ForceHandleCtrlC(false);
+  auto component = Renderer([&] {
+    screen.PostEvent(Event::CtrlC);
+    return text("");
+  });
+
+  int ctrl_c_count = 0;
+  component |= CatchEvent([&](Event event) {
+    if (event != Event::CtrlC) {
+      return false;
+    }
+
+    ++ctrl_c_count;
+
+    if (ctrl_c_count == 100) {
+      return false;
+    }
+
+    return true;
+  });
+  screen.Loop(component);
+
+  ASSERT_GE(ctrl_c_count, 50);
+}
+
 }  // namespace ftxui