use h5web 7.0.2-beta.0

This removes the background color of the TiledHeatmapMesh that was making a black square blinking when reloading the tiling in the tomo view. @sfisher if you need this background it in your case, let me know, it's just a matter of adding the mesh that was removed in TiledHeatmapMesh below it.

It also displays +/-Inf in images as values over/under the colormap limits rather than not displaying them.