Fixed Level transition and Fixed Gmod crashing.

[RaphaelIT7]

[#] Fixed a crash in Gmod related to ConVars (Thanks to Rubat who helped me find the approximate cause of the crash)

I don't exactly know why the removed delete statements crashed the game (HL2), but they did.

Related Issues: fixes #166 fixes #155 fixes #60

ToDo:

• [x] Fix Vehicles crashing the game when you sit in them and remove them (Crashed somewhere here)
• [x] Fix the mini-sourcesdk and remove the ConVar workaround mini-source-sdk pr: https://github.com/Joshua-Ashton/mini-source-sdk/pull/3