Investigate possible upgrade of Cesium

[pacesm]

Cesium is currently pinned to a fairly old v1.20 (

WebClient-Framework/bower.json

Line 24 in ad6db09

"cesium": "https://github.com/AnalyticalGraphicsInc/cesium/releases/download/1.20/Cesium-1.20.zip",

).

Possible upgrade to a newer version should be investigated.

Also note that ...

The cesium version was fixed to this one as it uses a specific way of rendering the dots. This is then overwritten by our deploy to make sure the shader uses a solution that does not create issues where dots overlap. Starting v 1.21 they changed how points are rendered, the points no longer disappear when displayed in a specific angle, but they create artifacts at the border of the points where some pixels become transparent.
If we update the version we will need to look at how they are doing the new rendering and see if we can overwrite their shaders if we want to achieve the smooth transition between points again. (Maybe this has been solved at some point already in latest releases) would need to probably look at breaking changes depending on which version we want to use.

also see #57