remove some more test redundancy and restore a missing and important nil check

just merging if statements

- Update .pro file - Rethink logic of TCPBase, fixes bug with failing to receive all bytes from engine when process end signal is received before tcp disconnect

Remove unused uCommands from uGearsHandlersMess

Fix lastGameType not being updated if game type was demo or save (fixes a crash) Previously, if you first played a normal game, then a demo, the “play again” button would appear, but clicking it would only crash HW. This fix will remove this button after a demo or save, because the frontend doesn't know how to restart demos or saves yet.

Fix desyncs when forcing rope re-selection after missing a shot or hitting bounce world edge Also re-introduce rope-reselection when touching ground

Fix desync when dropping weapon from parachute or jetpack

Backed out changeset 28210d2a9a36 (fixes bug #553) This fixes a desync when you take fall damage while roping and having a secondary ammo selected.

initialise previousGameState to something valid and not gsSuspend

Add Lua problems to the troubleshooting section of INSTALL.md