bug fix: notification's parameters were in surrounding "parameters" object

was:
notification: {
  parameters: {
    parameters: {      // <<< this one "parameters" removed
      state: true
    }
  }                    // <<<
}
use case insensitive comparison for device identifiers
write unhandled exceptions to the log file
DelayedTasks mix-in class introduced

now it's possible to use callLater() method for delayed tasks (such as register again or poll commands again)
all REST examples (simple_dev, simple_gw, zigbee_gw) are updated