TD rendering freeze fix

This is a fix for the Lava Mountain freeze issue from TD (KartKrew/TD#13) which can also occur in vanilla SRB2 as it turns out. Basically the issue occurs whenever an FOF with a single-patch texture with holes goes off the bottom of the screen far enough.

See merge request !159

Fix endless loop of R_DrawRepeatMaskedColumn if both sprtopscreen and sprbotscreen are CLAMPMAX (INT32_MAX)

This fixes the grid floors in TD's Lava Mountain freezing the game if they go off the bottom of the screen far enough (they have ACWRFL1A as the wall texture, which is a single patch texture with holes)

A spike bug no more

Jumping at spikes on FOFs in reverse gravity - most notably in ERZ3 - no longer teleports you downwards into the death pit beneath it.

See merge request !157

Fixed a stupid bug involving jumping at spikes on FOFs in reverse gravity caused by my own incompetence/assumptions.

This reverts commit 6476cf3c, reversing
changes made to 0186b90b.

Appveyor: compile with Mingw32 GCC 4.9.3

Let use an old GCC to compile SRB2

See merge request !112

Last few changes for 2.1.17

what it says on the tin

* Updated version number
* Added LJSonic to credits (and changed how I look in the credits to be less stupid)
* fixed resynching players seeing the host turn into a spectator for no reason

See merge request !155

Otherwise we can't force updates!

Netcode shit

*takes the cookie*

-Added a timeout for game state downloading to prevent definitive join freezes in some cases. The timeout has a minimum value of "jointimeout" and gets higher as the game state grows in size
-If the server tries to kick a joiner who is downloading the game state, they will get a timeout instead, because a regular kick would only happen once the game state has been downloaded
-Added a timeout for player ticcmd packets, again to prevent freezes to happen in some cases
-File/game state downloading is now faster, the speed is controlled by the "downloadspeed" cvar, in packets per tic
-The reason is now properly shown when the server refuses connection
-Changed the default values of "nettimeout" to 10 seconds (previously 15) and "maxsend" to 4 MB (previously 1)
-Added a "noticedownload" cvar that displays a message in the server console when someone is downloading a file

CMake: Fix nasm Linux builds

When compiling under Linux with CMake and nasm/yasm enabled, the operation would fail during linking with undefined symbols related to the tmap files.
This commit adds support for passing flags to the assembler and passes ```-DLINUX``` in order to compile.

After this change, binaries are successfully compiled with either nasm or yasm on Linux systems.
Tested on Ubuntu.

See merge request !153

Added transmaps to non modifying lump list.

CMake: split inline ASM code from vid_copy.s code

See merge request !151

Update Code::Block project

See merge request !145

Savegame hotfixes

Yes, this another netgame related fix! Named this "savegame hotfixes" rather than "ERCZ hotfix" or the like in advance of the fact we probably need a general branch for other $$$.sav fixes?

Anyway, fixes included in by this branch:
* ERCZ's lava falls now act as expected rather than being stuck in place for the map's duration, fixing all other known desynchronisation issues known in the map for the time being (yay)
* Changing sector tags in a map no longer causes joiners to netgames to have their SRB2 application stop responding etc
* Player names should no longer turn red in the console in gametypes outside of CTF/Team Match if a resynch occurs (not $$$.sav related, but it's related to netplay so I lumped it in anyway)

See merge request !150

Eggshield laser fix

Fix for http://mb.srb2.org/showthread.php?t=42250

See merge request !152

Fix egg guard shields being endlessly killed by lasers. Simply make sure they have health first before killing them!

One Eggscalibur fix

Use mobj->watertop instead of mobj->spawnpoint->z. CEZ3 is far from fixed in multiplayer, but this is still one less thing to worry about.

See merge request !148