Push Notification Plugin - first beta release
 - directly supports 5 providers:
  - Notify My Android
  - Pushover
  - Prowl
  - LiveNotifier
  - Trendoo (SMS)
Push Notification Plugin - beta2 release
 - plugin now uses MessageEvent event template
 - each provider listens to its own channel
 - new feature: override global provider params with event ones, so that we can send custom one-time notification easily.
 - some code cleanup