big changes:

- task manager working now in round robbin and returning after every task to arduino
- adding a system class which is managing all bigger things

lib/System/Timer.cpp

@@ -0,0 +1,28 @@
+#include "Timer.h"
+
+Timer::Timer() : _timeout_sec(0), _timeout(0) {
+}
+
+void Timer::setTimeout(const time_t timeout_sec) {
+  _timeout_sec = timeout_sec;
+}
+
+time_t Timer::getTriggerTime() const {
+  return _timeout;
+}
+
+bool Timer::isActive() const {
+  return _timeout != 0;
+}
+
+void Timer::reset() {
+  _timeout = 0;
+}
+
+bool Timer::check() {
+  return now() > _timeout;
+}
+
+void Timer::start() {
+  _timeout = now() + _timeout_sec;
+}