SVC_UpdateStringTable broken on client joining

[Earu]

For context I'm playing on x64 and I'm using the new lua code.

Turns out the SVC_UpdateStringTable lua handler is broken when joining a server with sourcenet.
After removing the lua handler no more crash whatsoever.

I tried changing https://github.com/danielga/gm_sourcenet/blob/update-lua-code/sourcenet/netmessages.lua#L1199 to if self.changed == 1 then which seems to match more the reading part of the handler and the game stopped crashing outright but would get stuck in the loading screen.

[danielga]

I've pushed some changes to garrysmod_common that should fix the module on x86-64. I've tested it on a Linux x86-64 SRCDS instance, with the Lua code from the update-lua-code branch.