rename viewOffsetX to viewMarginX, plus many more

[Geokureli]

rename viewOffsetX/Y to viewMarginX/Y, also making all of these public, so you don't need to use the new getViewRect, to get the camera's view margin in world space, you can just use viewMarginLeft/Right/Top/Bottom. As well as various other helpers: viewX/Y/Width/Height to get the camera view in the world.

Important distinction:

• view___ refers to the cameras view in world space. position a sprite at camera.viewLeft and it will be displayed on the left-most edge of the camera
• viewMargin___ refers to the margin around the camera caused by zooming in/out. Camera's zoom into their center, cutting off a portion of the world so a simple camera.scroll.x + camera.width won't suffice to get the camera's right edge, but camera.scroll.x + camera.viewMarginX + camera.viewWidth will, as well as camera.scroll.x + camera.viewMarginRight (or simply camera.viewRight)