Support Bazel build system (#1033)

Bug:https://github.com/ArthurSonzogni/FTXUI/issues/1032
Fixed:https://github.com/ArthurSonzogni/FTXUI/issues/1032

examples/component/slider_direction.cpp

@@ -19,7 +19,7 @@ using namespace ftxui;
 int main() {
   auto screen = ScreenInteractive::TerminalOutput();
   std::array<int, 30> values;
-  for (int i = 0; i < values.size(); ++i) {
+  for (size_t i = 0; i < values.size(); ++i) {
     values[i] = 50 + 20 * std::sin(i * 0.3);
   }
 

examples/dom/color_truecolor_RGB.cpp

@@ -12,7 +12,6 @@
 int main() {
   using namespace ftxui;
 
-  int saturation = 255;
   Elements red_line;
   Elements green_line;
   Elements blue_line;

examples/dom/graph.cpp

@@ -10,6 +10,7 @@
 #include <memory>                   // for shared_ptr
 #include <string>                   // for operator<<, string
 #include <thread>                   // for sleep_for
+#include <utility>                  // for ignore
 #include <vector>                   // for vector
 
 #include "ftxui/dom/node.hpp"  // for Render
@@ -49,6 +50,7 @@ int main() {
 
   std::string reset_position;
   for (int i = 0;; ++i) {
+    std::ignore = i;
     auto document = hbox({
         vbox({
             graph(std::ref(my_graph)),