Additional l4d2 models

Couple of textures added to blackicetexts

Added arc 1344 for use on Double junction curves

One prop added, a large support usually for viaducts or large bridges

Added some mprops for Blackprise

Added some combine lookout posts to the new folder in /regprops/citystuff/combine/. There are three versions that have a cover, no cover, and a wrap around barrier. You'd use this ideally above the ground, but don't let that stop you.

Added a single ramp

Added a road

Added TP3 straight pieces
144, 1280, 1472, 1552, 1568, 1728, 2064, 2176, 2496, 2832, 2848, 3264, 3600, 3712, 3968

Attempt to fix some models