CMake updates for library and samples to improve quality of life in VS

[chaoticbob]

Some changes to the CMake files to make it easer to work on Cinder from within generated Visual Studio projects

• Added corresponding header files to existing source files
• Added source groups that similar to the stock Visual Studio project
• Added FOLDER property to ci_make_app so apps can be organized into a folder
• Updated sample files to live in subfolders that follow their filesystem layout