add devterm_keyboard_mini init code

Code/devterm_keyboard_mini/debouncer.ino

@@ -0,0 +1,23 @@
+#include "debouncer.h"
+
+Debouncer::Debouncer()
+  : timeout(0)
+{
+}
+
+void Debouncer::updateTime(millis_t delta) {
+  if (timeout > delta) {
+    timeout -= delta;
+  } else {
+    timeout = 0;
+  }
+}
+
+bool Debouncer::sample(bool value) {
+  if (value || timeout == 0) {
+    timeout = DEBOUNCE_MS;
+    return true;
+  }
+
+  return false;
+}