Display node's IP when printing the "sending file to node n" message, if noticedownload is turned on

* if you sent it to a client rather than the server, game over, your connection is closed
* if files that don't exist or are too large are requested are listed, game over, your connection is closed (they should have been checked on YOUR side beforehand, silly)
* if the server has downloading disabled anyway, ...yeah, you get the idea

Don't worry, I made sure Got_RequestFilePak cleaned up the full file request list for the node in case of failure

Added a bunch of missing checks to prevent non-server players from sending other non-server players stuff

On second thought, this was probably unnecessary anyway.

This reverts commit 1078a642.

SDL fixes and cleanup

Mostly cleanup tbh. I noticed a few things that bugged me when examining SDL's code recently, thought I might as well fix them up a bit.

These changes definitely does not affect netplay, so this can be merged to master just fine.

See merge request !183

I_GetConsoleEvents: Split KEY_EVENT code into a function of its own, like with I_GetEvent's event types

One benefit of this is that event_t data need only be created if KEY_EVENT is found, since the other event types never do anything anyway

Not really important or anything, but checking render_soft == rendermode rather than rendermode == render_soft always bugged me. And it's not consistent with the rest of the source code (or at least most of it) anyway.

If modenum was < 0 or >= MAXWINMODES, that would make windowedModes[modeNum] be out of bounds and possibly crash the game.

I_FinishUpdate: OglSdlFinishUpdate should never run for render_soft, even if screens[0] somehow is NULL

Update to v2.1.18

Exactly what it says on the tin.

See merge request !180

Don't worry, I remembered to update MODVERSION as well this time :)

Jet Jaw crash fix

Turns out not having MF_SHOOTABLE can cause the Jet Jaw to endlessly loop between the two states, until somehow LUA_CallAction inexplicably causes Z_StrDup to crash anyway (that one's a mystery to me, I'm not going to look into it right now). I tweaked A_JetJawChomp so this endless loop can't happen anymore.

See merge request !176

Invalid node hotfix master

Quick hotfix to prevent `Net_CloseConnection` from crashing if the node's number is invalid.

See merge request !179

obj folders fix

Partial backtrack of changes I made in !174. Apparently removing all the `.gitignore` files from `/objs`'s subfolders removed the only reason Git was keeping the folders alive (Git doesn't care about empty folders as it turns out). So now they have `.gitignore`s again, with a warning in each not to remove them.

See merge request !177

Re-add all the folders present in objs before my .gitignore changes, by adding .gitignore files again to keep them from disappearing

.gitignore stuff

The following changes have been made to `.gitignore` files in the objs/ and bin/ folders:
* All the `.gitignore`s living in subfolders of objs/ have been done away with and replaced with a single `objs/.gitignore`, covering all the things that the subfolders ignored before (including depend.ped, if anyone is like me and has to remove that file manually)
* All the `.gitignore`s living in subfolders of `bin/Mingw` ignore .exes of any name, not just srb2win/srb2dd/srb2sdl. en.mo is also ignored now... or rather any .mo file (just in case). This is mostly for my own sanity and that of anyone else who uses EXENAME=[name.exe] when compiling with MinGW.

If you're not sure what `.gitignore` does exactly, as far as I'm aware it literally just tells Git what to "ignore" (or rather, not track), so anyone using Git GUI or some other Git program etc doesn't have to see changes certain files and can't accidentally commit the files or whatever.

See merge request !174