Increase cost of DOME from 1600 to 1800

Just move this slightly later, and make DOME-first rushes a bit more
risky.
Merge pull request #4810 from chrisforbes/delay-dome-balance

Adjust RA balance
Add changelog entry for Radar Dome cost tweak.
Merge pull request #4857 from pchote/ra-balance-changelog

Add changelog entry for Radar Dome cost tweak.
add a spectator player that shares shroud with everyone

closes #4607
Merge pull request #4656 from Mailaender/everyone-shroud

Added a spectator player that shares shroud with everyone
Let radar dome detect cloaked units
Let attack dog detect cloaked units
Let mobile radar jammer detect cloaked units
Let cloaked units optionally uncloak when unloading
Adjust tooltip description for destroyer to mention its cloak detection ability
Remove cloak detection from ca and lst. Increase pt's cloak detection range to 4 and render a cloak detection range circle for it
Add CloakTypes to prevent ships from detecting cloaked non-submarine units etc
Adjust tooltip description for gunboat to mention its cloak detection ability
Implement phase transport
Change sniper to use ReturnFire instead of HoldFire stance by default
Remove actor generation increment when entering cloak
Let sniper detect cloaked units
Let only mine layers detect enemy mines
Let spy plane detect cloaked units