* Add handling of portable mode when updating
Additionally:
1. Changed getting version from internally rather than from RELEASES file
2. Added PortableDataPath as a constant so can be used to determine if portable mode is used
* Fix incorrectly wired auto update event handler
* Fix Sys plugin missing Shutdown command icon
* Add check update command to Sys plugin
* Add message if current Wox version is latest
* Add default silent when auto checking updates in background
Silent when current is still the latest version
* Move UserData folder to new version location
* Changes per review
1. Move IsPortableMode to Constant
2. Merge if statement
* Per comment- change variables to be more descriptive
UpdateInfo and UpdateManager renamed
* Per comment- Add exception handling and message if failed.
1. Reorder the sequence of initialization of UserSettings.
2. Use dictionary for CustomizedPluginConfigs, so code logic like
`.FirstOrDefault(o => o.ID == id);` are removed
3. part of #389
