Cruor

CairoSurface using Float64 for width and height

5

Is there a specific reason why they are stored as Float64s?. The documentation for Cairo uses integers for these. For example [cairo-image-surface-get-height](https://www.cairographics.org/manual/cairo-Image-Surfaces.html#cairo-image-surface-get-height).

Memory leak when destroying a surface

10

`destroy()` on surface (`CairoARGBSurface`, to be exact) doesn't seem to get removed properly. This is tested on windows running ``` julia> Cairo.VERSION v"0.6.0" julia> Pkg.installed()["Cairo"] v"0.5.1" ``` and Linux with...