QuakeSpasm-OpenVR 0.96.3a

Changes:

• Merged QuakeSpasm v0.96.3 (see changes here)
• Add weapon offset for Copper axe (v_axe2.mdl) by default. This makes the offset work by default for all mods, that use Copper.
• Update openVR to v2.5.1
• Fix getting blocked without reason on elevator-ride (cherry-pick from Ironwail by @andrei-drexler)
  • Add sv_gameplayfix_elevators cvar
  • If an entity is standing on a platform and gets blocked by it, try nudging it up a bit first to get it unstuck.
  • Cvar values:
    • 0 = no fix (vanilla behavior)
    • 1 = fix players only
    • 2 = fix all entities (default)