Changed target Fx to .NET 4.5,
Changed target Fx to .NET 4.5,

because this will enable us to target operations on finite sequences (such
as PickRandom, ToSet, ToQueue, etc.) on IReadOnlyCollection<T> instead of
IEnumerable<T>.

The original motivation for targeting .NET 3.5 was to make Champagne as
generally useful as possible. This should still be a goal, but will
probably mean that we'd need to look into conditional compilation at a
later date, in order to make a special build for .NET 3.5.

Perhaps other users also need a version for Windows Phone, etc...

GreanTech/Champagne,GreanTech/Champagne