Add missing NSControl.InvalidateIntrinsicContentSizeForCell method
Makefile: pass BMAC_OPTIONS to bmac
Build against 4.0 so binaries still work on Mono 2.10.x
Bind NSConnection and friends
NSImageView.Image: allow setting to null
Fix constructor construction since NSObject.Retain changed its signature and add Selector.Autorelease[Handle].
Provide generic GetRootProxy methods for NSConnection
This returns a proxy to a remote object, so we'll generally want it
to return a binding typed as the remote object's interface.

Runtime.GetNSObject sends the "class" message to determine the type of
binding to create, but that always returns NSDistantObject in this case,
so bypass it and explicitly create the type of binding we want.
maccore requires v4.5 now to build.
Revert "maccore requires v4.5 now to build."
We want to continue supporting 4.0

This reverts commit 3847e3d14142228dbde21371e356defd26463f24.