Add useful tool textures (and fix toolsinvisibleladder)

[SirYodaJedi]

• tools_viscluster: (from BMS) same as toolstrigger, but intended for visclusters
• toolsinvisible_nonsolid: like toolsinvisible, but works on brushes with %compilenonsolid mats
• toolsinvisibledisplacement: (from TF2) for displacement clip brushes, since nodraw doesn't work there
• toolsinvisibleladder - fixed version that doesn't cut visleaves (and has translucency in editor)
• toolsnodraw_nonsolid: like toolsnodraw, but works on brushes with %compilenonsolid mats
• toolstrigger_soundscape: (from BMS) same as toolstrigger, but intended for soundscape triggers

If you'd prefer to not take the VTFs from BMS+TF2, just suggest a free font and I can recreate them from scratch.

[SirYodaJedi]

If you'd prefer to not take the VTFs from BMS+TF2, just suggest a free font and I can recreate them from scratch.

[BreakinBenny]

This could come in handy. By the way, some of these are in TF2 Classic as well:

• toolsinvisibledisplacement
• the updated toolsinvisibleladder
• toolsviscluster

If you like, you can rename the current VMT and VTF for the last one...