(svn r631) Merge r440, r444, r485, r630 to trunk:
r440
Move screenshot function declarations to new file screenshot.h
Clean up screenshot.c a bit, mostly whitespace, alloca() -> malloc() and checking return values
r485
Remove unused field from struct ScreenshotFormat

(svn r607) -Patch: [ 985102 ] static cleanup
Thanks to lvoge

(svn r240) -Fix: desync on subsidy generation
-Fix: sometimes commands got executed to early on some clients
-Feature: universal event packets for transmitting subsidys

(svn r223) -Fix: Const correctness and miscellaneous fixes. Thank you Tron for your diligent fixing of warnings (and some possibly bugs) (Tron)
-CodeLayout: Remove trailing spaces and Windows linebreaks

(svn r214) -Feature: CMD_NET_INSTANT [just in time command handling over network] (sign_de)
-Fix: Only server can pause in network, action disabled for clients
-Fix: Direct Connect editbox can handle up to max ~35 characters

(svn r209) -Fix: network code based desync
-Feature: framesync packets to hold the clients framecount near the servers
-Fix: command queue now aligns the commands to be processed right after an sync or framesync packet
-Fix: added stubs for compiling without network

(svn r207) -Codechange: randomizer handling
-Fix: desync problem fixes
-Fix: server doesnt hang anymore when a client timed out
-Feature: low latency connection enhancements [*net_sync_freq, *net_ready_ahead]

(svn r186) -Add: debug 'net' for network debug (sign_de)
-Fix: desync problem (server was not waiting for clients) (sign_de)

(svn r173) -Network: [1023231] Debug Code + ErrorBoxes + Load Game/Scenario. Added some more desync debug code and replaced some of the error() calls with some better error boxes. Hopefully find desyncs easier (sign_de)
-GUI: Change some network GUI stuff (Darkvater)

(svn r169) -Fix: move around sort-widgets a bit so it looks more natural
-Fix: savegames are sorted with newest date first by default
-Codechange: refine sorter functions
-Fix: fixed linux warnings (tokai)

(svn r127) New feature: ingame console. (sign_de)
Press tab to open the console, more info in docs/console.txt

(svn r122) Change: exclusive transport rights are now stored per town instead of per station
Exclusive rights from old savegames will be reset.

(svn r106) New network core (by sign_de)

Features:
* network core is dynamicly loaded when needed (-n isn't needed anymore)
for easy switching between single and multiplayer. But commandline
shortcuts are still enabled:
-n = autodetect network server
-n [ip] = connect to the server
* udp now uses 2 different ports
- you can run 1 server and serveral clients on one pc
- the clients udp-socket gets unloaded when the
network game starts
- the servers udp-sockets remains online to allow the
network gui to detect itself
* new gameinfo structure
this struct is available for every online/lan game
* dynamic NetworkGameList

(svn r85) -Add: initial commit of new AI (enable in Patch menu)
-Add: generalised A* Algorithm
-Add: generalised queues (Fifo, Stack, InsSort, BinaryHeap)

(svn r68) -Fix: [1009621] build in pause is now a cheat instead of a patch (truesatan)
-Fix: Placing/editing signs signs is possible in paused mode

(svn r66) -Fix Station list updated on station deletion/station rename
-Changed debug messages to comply with DEBUG(name, level) heuristics

(svn r2) -Fix [993829] UDP Fixes (lucaspiller)
-Fix change 255/0xFF to OWNER_SPECTATOR for
spectator stuff (TrueLight)