Initial OSX commit using Xcode
More framework changes

- Added Surface class to manage loading images
- Added Texture class to manage surface in texture memory
- Added Window class to manage concept of a window
- Updated code to use these
- Updated Xcode project with SDL2_image
- Updated Xcode project with temp map

Note:
- Windows project is not updated yet
- Nothing is actually rendered yet
Updating Windows Codelite project

- Updated SDL_image.h includes
- Updated .gitignore

Note: OSX build may be broken with include path change in
           surface.cpp