增加virtual功能
Merge branch 'master' of github.com:ContestHunter/ContestHunter
Merge branch 'Virtual'

Conflicts:
	ContestHunter/ContestHunter.csproj
	ContestHunter/Database/CHDB.Context.cs
	ContestHunter/Database/CHDB.edmx
	ContestHunter/Database/CHDB.edmx.diagram
	ContestHunter/Database/CONTEST.cs
	ContestHunter/Database/RECORD.cs
	ContestHunter/Database/USER.cs
	ContestHunter/Models/Domain/Contest.cs
	ContestHunter/Models/Domain/Problem.cs
	ContestHunter/Web.config