-Use dual-mode socket & DnsEndPoint to handle all domain name connection.
-Move all socket creation into one single function.

So that we could treat domain name just like ipv4 & ipv6 address.
This also solves the async domain solving problem because the os will
hanlde it for us.

# Conflicts:
#	README.md
#	shadowsocks-csharp/Controller/Service/AvailabilityStatistics.cs
#	shadowsocks-csharp/Controller/Service/PACServer.cs
#	shadowsocks-csharp/Controller/Strategy/SimplyChooseByStatisticsStrategy.cs
#	shadowsocks-csharp/Data/cn.txt
#	shadowsocks-csharp/Model/Configuration.cs
#	shadowsocks-csharp/Model/LogViewerConfig.cs
#	shadowsocks-csharp/View/LogForm.Designer.cs
#	shadowsocks-csharp/View/LogForm.cs
#	shadowsocks-csharp/View/MenuViewController.cs

1. Add Logging.Info()
2. Console.WriteLine() -> Logging.Info()
3. Console.WriteLine() in exceptions -> Logging.LogUsefulException()

1/ removed dual empty line
2/ removed tailing spaces
3/ converted tabs into spaces
4/ added some TODO comments