File uploading and downloading added. Change file size for upload.
Fix file extension for client. Deleting file link in file link table on downloading.
Merge remote-tracking branch 'remotes/origin/Slava' into Vadzim

Conflicts:
	FileExchange/FileExchange.BLL/Concrete/FileService.cs
	FileExchange/FileExchange.BLL/FileExchange.BLL.csproj
	FileExchange/FileExchange.BLL/Interfaces/IFileService.cs
	FileExchange/FileExchange.DAL/ConfigManager/ConfigManager.cs
	FileExchange/FileExchange.DAL/FileExchange.DAL.csproj
	FileExchange/FileExchange.WebUI/App_Data/FileExchange.mdf
	FileExchange/FileExchange.WebUI/App_Data/FileExchange_log.ldf
	FileExchange/FileExchange.WebUI/App_Start/AutomapperConfig.cs
	FileExchange/FileExchange.WebUI/Controllers/FileController.cs
	FileExchange/FileExchange.WebUI/ViewModels/FileViewModel/FileViewModel.cs
	FileExchange/FileExchange.v11.suo