Update NuGet packages to 1.1 and lower NETStandard to 1.5

[dustinmoris]

Hi, I saw that RazorLight targets NETStandard 1.6 and this is due to some dependencies that it has. When you upgrade the .NET dependencies from 1.0 to 1.1 then you could lower the NETStandard to 1.5, because unfortunately Microsoft.AspNetCore.Razor.Runtime doesn't target anything lower, otherwise you could have gone as low as 1.3 which would have been ideal.

[toddams]

Good point!
When I started developing this Library - NETStandard 1.6 was covered by .NET 4.6.2, but since then situation has changed.

[toddams]

Seems like we can't lower NetStandard because of Microsoft.Extensions.DependencyModel package that is used to discover assembly dependencies while building a template.

It is possible to use it on NetStandard1.3, but it does not have all the required API
You can take a look on it's limitations here (https://github.com/dotnet/core-setup/blob/master/src/Microsoft.Extensions.DependencyModel/DependencyContext.cs)