v0.72.0 PCL now supported

The main purpose of this release is supporting PCL projects. You need to add the Realm NuGet to both your PCL projects and your ultimate platform .IOS and .Android projects.

If you only add the Realm NuGet to your PCL project you will get a runtime exception saying something like:

The PCL build of Realm is being linked which probably means you need to use NuGet or otherwise link a platform-specific Realm.dll to your main application.