- Remove Linq based code and change TargetFrameworkVersion to v2.0 instead of v3.5

Since there was minimal use of v3.5 features (and both v3.5 and v2.0 both use the .Net 2.0 CLR) it makes sense to rebuild this without any of the extra 3.5 libraries pulled in to let more people make use of this library in a .Net 2.0 only context.