Refactor per-player shrouds & fix shellmap shroud.
Display selection decorations to allies & observers.
More shroud refactoring.

This introduces a hash on Shroud which ShroudRenderer
can observe, removing the need to explicitly twiddle
a dirty flag between objects.

Shroud disabling is now done via RenderPlayer, so
enabling the cheat or winning/losing will now give
vis equivalent to an observer.
LocalPlayer.Shroud is never the right shroud.
Fix selection decorations being drawn behind fog.
allowUPnP is a bad name for automatic port forwards

also check it by default if all those checks went well
fixes #2797 lintian claims that our package is bad
polish the temperat shellmap a little

- silence the gun sound a bit
- remove the flickering mig
Fix shroud for observers observing a player after win/loss.
Allow maps/mods to properly disable fog or shroud (or both).
Making bridges indestructible for now.

Making bridges indestructible.
Rationale: 
-many maps don't work when bridges are destructible (most or all of the crossings are bridges)
-bridges will be repairable in the future. At this point, an engi can come and re-open it, but in the meantime, they shouldn't be destroyed.
-if someone wants to make a map with destructible bridges, they still can, by editing the .yaml themselves. This should be the default, though.




(FWIW, bridges were not destructible in C&C 1.)
replaced all explosion numbers with names

Explosions all have a name description now instead of a vague number.
Sniper range reduced from 7 -> 5.5

Sniper range of 7 seems ridiculous, since it's a one-shot kill, and you can build multiple. (I support building multiple). Surprised I never noticed this issue before.
The range in C&C 95 was 5.5. 
The ScanRadius is set to 5, which is probably why we haven't noticed any OP problems. 
It's also a bit ridiculous since the unit's sight radius is only 5.
housekeeping: moveing artillery BuildPaletteOrder
fix Chinook "returning to base" problem

Chinook had "Re-arms at: HPAD" entered in its rules, even though it has no weapons. This is what caused it to return to base when you hit 'F' instead of land.
Now it lands again when you hit F. *phew* so happy :)
housekeeping: moved arty over some more in menu
Rework centre of desert shellmap. Adjust unit balancing.
Add unit production and other buildings to desert shellmap
Merge pull request #3029 from Mailaender/lintian-fix

Changes DEBIAN/md5sums permissions to 0644
Merge pull request #3030 from Mailaender/shellmap-polish

Removed some annoyances from the RA temperat shellmap