- Make QuickGraph core dll cls compliant

[Yannike]

Making the core dll cls compliant involves only adding a flag to the assembleinfo.cs. Everything in there is already cls compliant and it doesn't prevent any non cls compliant project from using it, but it let cls compliant expose class and interfaces.

[KeRNeLith]

This seems indeed a useful change. I also took this opportunity to make other assemblies CLS compliant except the MSAGL one.