Code review comment for lp:~stellarium/stellarium/toastImages

TOAST is "tessellated octahedral adaptive subdivision transform" (details: https://arxiv.org/pdf/1505.02291.pdf) + see section "2.3.2.8.1 The TOAST Projection" (skyview.gsfc.nasa.gov/current/docs/skyviewinajar.html)

TODOs - I hope Fabien can help with it (I can't add/change DNS names).

Network behaviour: it's more to the StelTexture class behaviour