* 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. remove unnecessary events from MainViewModel
2. remove usage of Obsolete api (show, hide etc)
3. fix space problem in #660
4. part of #486
5. fix up/down key bug introduced in 92b7ca6a1bafd254e39ee92812ff691906cd85c1
6. fix#678
1. Fix can't find Result.ctor bug for plugin introduced in
c0889de1f9ae460b2cc189eb59e5bd90ddb7d17e
2. use %APPDATA% for all data, part of #389
3. MISC
1. Remove ItemDropEvent
2. Remove ShowContextMenus from API
3. Fix context menu item can't be opened ( #535 ), bug introduced from PR #494 (commit 45dbb50)
4. Move open result command and load context menu command back to
MainViewModel
5. unify load context menu logic
6. other performance enhancement and potential bug fixed
