v0.4.9

Add Event for listening to notifications and Operation for sending notifications && Add a setting entry for enabling / disabling plugins && Add compatibility checking for plugins && Inform future changes && Bug fixes

• Add NotificationEventPlugin to listen to notifications and SendNotificationOperationPlugin to post notifications
• Add a setting entry to enable or disable plugins
• Add PluginDef.isCompatible() to check for the compatibility of plugins before using them
• Add a prompt screen to inform the user about possible future changes and actions to take
  • Currently, v0.5 (or later) will drop the support for old data formats, so users should convert the old formats to new formats (by using the conversion provided in the setting screen).
• (Lollipop+ / SDK 21+) Fix the function of RingerModeOperationPlugin to set to silent mode
• Fix the problem of re-requesting permissions
• (dev) Explicitly fix 0 as infinity for OperationPlugin.maxExistence()
• (dev) Remove the ordering of plugins from PluginRegistry (moved that to where it is needed)