Floorplan does not show [11" MacBook Air mid-2011] [macOS 10.10.5]

[mitchmindtree]

It seems the floorplan image is too large for the amount of video memory available on this small macbook air. As a result the the floorplan displays either glitched or totally blank. Note that although the PNG is 1.5mb, when loaded as a raw texture the size is significantly larger (~300mb).

Unfortunately the GL implementation on the macbook air gives no indication that this is a problem and does not produce any sort of error or console output when this occurs, so it's hard to fix this at run-time (e.g. try re-size and resample the image before attempting to load into the texture again).

It's possible to work around this my reducing the size of the floorplan. Be sure to update the floorplan_pixels_per_metre if you do this. Note that obviously it will look a little less crisp as a result. This could be fixed in the future via #114.

@freesig you have a macbook air right? If so, just a heads up that you might run into this.