NPOI requires GDI+ dependency even on sheet creation without using column auto-sizing

[msvprogs]

This is critical for Linux/Docker-hosted services. Magic with libgdiplus package installation didn't work in my case.

Possible solution: do not create AutoSizeColumnTracker in the constructor but move it to Lazy<AutoSizeColumnTracker> so it will be created on demand. My solution: msvprogs@71788be

[tonyqus]

But why do you want to totally get rid of libgdiplus?

[msvprogs]

I didn't say so :) But let's only use it on explicit calls of auto-sizing methods or properties. Current version of sheet constructor triggers some static initialization method of GDI+, which causes an exception on Linux. With Lazy<> problem is gone (GDI+ is called only when using auto-sizing methods).

[tonyqus]

mmm....looks to be a good idea. Can you create a PR for this?

[msvprogs]

Ok. https://github.com/tonyqus/npoi/pull/377

[tonyqus]

code merged