Update NuGet.Core to 2.7 and fixed regressions.
Merge branch 'stable'

Conflicts:
	Sources/SymbolSource.Gateway.NuGet.Core/SymbolSource.Gateway.NuGet.Core.csproj
	Sources/SymbolSource.Gateway.NuGet.Core/packages.config
Removed openwrap support
Updated to nuget 2.8, MVC 5
Allow configuration of data/index paths