[Teton] Buffer current command for executing.

sys/teton/terminal.h

@@ -0,0 +1,17 @@
+#include <glacier/string/string_builder.h>
+#include <mammoth/input/keyboard.h>
+
+#include "framebuffer/console.h"
+
+class Terminal : public mmth::KeyboardListenerBase {
+ public:
+  Terminal(Console& c) : mmth::KeyboardListenerBase(), console_(c) {}
+
+  virtual void HandleCharacter(char c) override;
+
+  void ExecuteCommand(const glcr::String& command);
+
+ private:
+  Console& console_;
+  glcr::VariableStringBuilder current_command_;
+};