Separate C# classes into Internal and Public Change-Id: I12b90fc0eb411d0d4df9dcbf6d79e70a46cc4fb8
Combined Stage and Window class, and removed Stage class Change-Id: I1e7699c3b11c332195d4f8193626b48d8185ea6c
New directory structure for C# Change-Id: I418b9af4be2cdc92913da8a1e8ffeb6282961002