Limit Castle.Core to <5.0 to avoid breaking changes

[Jevonius]

With the release of [email protected], there are a number of breaking changes (for example castleproject/Core#563) that affect Windsor.

Example code that blows up:

var container = new WindsorContainer().Install(FromAssembly.Named("Does.Not.Matter"));

Gives an exceptions along the lines:

System.TypeLoadException : Could not load type 'Castle.Core.Internal.PermissionUtil' from assembly 'Castle.Core, Version=5.0.0.0, Culture=neutral, PublicKeyToken=407dd0808d44fbdc'.

System.TypeLoadException : Could not load type 'Castle.Core.Pair`2' from assembly 'Castle.Core, Version=5.0.0.0, Culture=neutral, PublicKeyToken=407dd0808d44fbdc'.

This PR limits the upper version of Castle.Core to < 5.0, so that these changes don't bite consumers at runtime, until Windsor is updated to support the new version.

Took the opportunity to remove unnecessary references to Castle.Core in Facility projects that transitively include it already by referencing the base Castle.Windsor project.

[jonorossi]

There are a bunch of unreleased changes in master including some changes to target frameworks:
v5.1.1...master

Let's leave that in master so we can do what's relevant for today, I've created a branch off v5.1.1 to work in.

[jonorossi]

@Jevonius Your changes look good. Can you rebase off the releases/5.1 branch to remove the changes we don't want to ship.

[Jevonius]

@Jevonius Your changes look good. Can you rebase off the releases/5.1 branch to remove the changes we don't want to ship.

I think I've done this now (haven't done a huge amount of rebasing before).