Adjusted a couple of tunnel5 props to have more detail

Fixed Tunnel4 set's textures, after a couple of years lol.
Fixed tunnel5 hitboxes and textures. Oops

Added busstop2 to /regprops/citystuff/
Added bridge5 to /infra/bridges/
Added ob_tunnel1 to /mprops/overbuild/
Added ob_tunnel2 to /mprops/overbuild/
Added tunnel5_512, 1024, 1536, 2048, 3072, 8192 to /infra/tunnels/
Added RSG straights: 24, 832
Added RSG straights @ 45 degrees: 608

Added bloody loads of textures

Added some textures
Added 6 track pieces:
Grade 4 + 5%, 2048 length
Radius 3 and 4 for the 2048 and 3072 tracks

Added office14

Added 5 buildings: housing 47, 48, 49, 50, and office13 to building/nonacc/

Added 60 new textures to /blackicetexts/, which are all brick textures. Just wanted to get this out before I forgot.

Added a couple of bits for gm_lifevon

Added acc_office1 to buildings/acc/

Added new cranes, made from scratch as the old ones were removed. These can now be found in regprops/industrial/cranes. IGNORE regprops/cranes, as this is an old folder that I can't remove as some maps are using models based in here - namely the containers. That is all they're used for.

crane1_256 to 1024, with 5 of them having cabin versions.