add open on lan option

Add an option to choose whether to open on lan or not.
add log switch and modify detector

Add an option to select whether to open log or not.
Add a detector to check whether the server setting changed.
small bug

Fix a small bug
add modify detector

Don't reload server if config not change.
add about form

Add an about form instead of just open link.
Merge remote-tracking branch 'origin/master'

Conflicts:
	shadowsocks-csharp/Controller/ShadowsocksController.cs
	shadowsocks-csharp/View/ConfigForm.cs