[Teton] Buffer current command for executing.

sys/teton/terminal.cpp

@@ -0,0 +1,20 @@
+#include "terminal.h"
+
+void Terminal::HandleCharacter(char c) {
+  console_.WriteChar(c);
+  if (c == '\n') {
+    glcr::String str = current_command_.ToString();
+    ExecuteCommand(str);
+    current_command_.Reset();
+  } else if (c == '\b') {
+    current_command_.DeleteLast();
+  } else {
+    current_command_.PushBack(c);
+  }
+}
+
+void Terminal::ExecuteCommand(const glcr::String& command) {
+  console_.WriteString("Executing: ");
+  console_.WriteString(command);
+  console_.WriteString("\n>");
+}