ex_velothi_hilltent_01 LOD'd and further optimized collision

[BethOfDeath]

• Combined some parts of collision geometry to reduce volume. Split beam ends off and combined them into the resulting support collision. Deleted faces from underside beam collision which can never be collided with.
• UV work on guarskin (not perfect, but better I think) and rope. Also fixed left side where guarskin was not fulling embedded in the pole and so showed a seam.
• Adjusted wood frame for guarskin to fix pole squash and clipping with rope on top where poles meet
• Fixed rope "guardrail" rope changing textures from tx_rope_brown_02 to tx_ropestrip_01 and fixed UVs to match
• Fixed thin rope down at end of tx_bridgeropes leftmost (looking at front) mesh, as its top did not meet the horizontal rope and just hung free in space.
• Retopologized endgrain and adjusted UVs to better center them. Reduced from 100 to 86 tris.
• Unstretched UVs on forks of wood mesh. I wasn't able to completely eliminate the seams.
• Merged tx_bridgeropes meshes and then UV islands
• Added 3 more LODs reducing thin triangles and drawcalls.
• Vanilla: 127715 bytes; new: 166595 (+30%)