Compare pointers not contents.
Merge pull request #2709 from fluffyfreak/fixTerrainPtrCompare

Compare pointers not contents.
Allow stars as a hyperspace target to avoid long in-system travel.
Cycle through stars when re-selecting same system in sector view.
Allow to select star as hyperspace target in system info view.
Draw sectorview stars as billboard sphere impostors, in one batch
split camera frame state out into a separate class so it can be reused
single renderer for the whole camera
use the naive frame transform, not the interpolated one

I only roughly understand why this is ok. I think still works sanely
because all the incoming positions are already interpolated. regardless,
it works, and will simplify things for me soon
remove attrib save. direct GL calls suck, and renderstates should make this unnecessary anyway
lift draw transform setup up to the context
draw billboards for distant terrain objects instead of spikes
Add a bit of ambient to the sectorview spheres
Merge branch 'hyperspace_target_star'
Remove the cached Terrain pointer.
Store only the data we actually need from it.
Merge remote-tracking branch 'luomu/niceify-sectorview'
Merge branch 'camera-refactor'
allow UIView to be "untemplated"
make the new ui available to all in-game views
move UI update & draw onto the mainloop and draw after the old UI