Adds an Android Library project so that the dll can be built from source...

.... Perhaps I'm unaware of another way to set this up, but I could not coax the Vernacular.Catalog project into building with the Mono Android framework and so the #if __ANDROID__ got excluded from all builds of the Catalog project which disables Android applications from using AndroidCatalog. The Android Library project uses file linking to reference the main Vernacular.Catalog project. The developer only needs to build the Vernacular.Catalog.Android project to produce the dll necessary for use inside of an Android project. If this is unnecessary, please share the steps for building the Vernacular.Catalog dll for Android.