Sector View. Added options to hide vertical lines and out-of-range star names

changelog, cleanup
move terrain shader shadows from vert to frag
fix stupid bug in discCovered in Camera.cpp
use good maths in terrain frag (finishing 913e1867)
Merge pull request #2177 from zugz/eclipse

eclipse fixes
Merge pull request #2174 from UncleVasya/SectorView_tweak

Sector View tweak
ModelBody wasn't actually getting the list of old lights due to passing by copy instead of reference. Also just tidied it a bit.
Merge pull request #2179 from fluffyfreak/BugFixes

Some minor bug fixes.
Change UI label from: "Draw labels out of range" to "Label out-of-range systems"
Merge pull request #2180 from fluffyfreak/Relabel

Relabel SectorView toggle label as planned.
data/lang/Polski.txt - #2174
Merge pull request #2181 from radius75/Polski.txt

data/lang/Polski.txt - #2174