Move GetWindows10SystemThemeSetting() to Util.cs
WindowsThemeMode use enum
Status var windowsThemeMode rename to windowsThemeMode
Used `if else` to replace `switch case`
Delete legacy commint (Some code).
Increase contrast for icon.

Added Config Form hint text

Add new hints and fixed some old interaction bugs

Fix udp relay

fixed issue #2371

Fixed a bug with + in query

Support Windows 10 1903 Light Theme (Menu icon color)

Plugin section

Plugin arguments tooltip

When error code is SocketError.AccessDenied/10013(WSAEACCES), the port is reserved by system and you may not find the process name in `netstat`.
 https://github.com/shadowsocks/shadowsocks-windows/issues/1835#issuecomment-453528715

Add "Apply" button to Editor Servers form

Enhance context menu  for System proxy and it's mode.

add "basic access authentication" support for http proxy @rickryo

Add check box to toggle plugin argument input

Removed unused array allocations

Improve the code readability useProxy test condition

Mentioned in PR #2219

Marked ApplicationRestartFlags with Flags attribute

DumpRegisteredEncryptor

Update PAC to handle user rules in a better way

PAC will check the user rules first to find whether the URL should be connected via PROXY or DIRECT. If it does not match, then go to check GFWList rules.