* Fix index check in CSelectSlide.RenameValue
The check used && instead of ||. An index cannot be negative and out
of range at the same time, so the check never returned early and an
invalid index caused an ArgumentOutOfRangeException.
* Allow textures to be disposed more than once
CTextureBase.Dispose threw ObjectDisposedException on a second call.
Dispose must be safe to call multiple times, otherwise freeing a
texture twice crashes the game.
Return early instead. CD3DTexture and COGLTexture also check
IsDisposed first, so a second call does not free the GPU texture
again. This matters for OpenGL, where the texture name may already
belong to another texture.
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Co-authored-by: Florian Ostertag <flokuep@users.noreply.github.com>
