Cleanup part 2, make ye old 2.1.18 warning a debugfile only message, and make the node == -1 have its own debugfile only message too

Also get rid of a stray newline

textcmd[0] for PT_NODETIMEOUT can't hold anything < 0 anyway, and you'd probably have to really try to get >= MAXNETNODES

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