Shader override fails when another game's bin folder is in PATH

[SlidyBat]

Describe the bug
To override shaders we rely on the stdshader*.dll files not existing. However, some users, mostly mappers, have other game's bin folder in their PATH which makes the engine try to load stdshader*.dll from there.

To Reproduce
Add a bin folder that contains stdshader*.dll to your PATH envvar. For example you could add C:\Program Files (x86)\Steam\steamapps\common\Team Fortress 2\bin. Try running Momentum and you'll get a launch error about overriding shaders.

Expected behavior
People have the bin folder in their PATH in order to use the mapping tools in the command line from anywhere. Ideally we shouldn't interfere with this and allow running Momentum regardless of what the user has in their PATH.

Potential fix
We could add logic in the game to remove other source engine games bin folders from the PATH at runtime. Would have to make sure that this happens before the engine loads the stdshader DLLs.

[Gocnak]

Engine access fixed this. Closing.