TE: add new view modes

[WalrusTR]

It could be useful add some new view modes to TE:

• [x] Show moveables and/or statics' collision/visibility boxes;
• [ ] Wireframe override for both moveables and/or statics;
• [ ] Draw rooms untextured but with wireframe override, no lighting (similar to "Draw in wireframe" mode + "Show sheen" in WADTool edit mesh)
• [ ] Complete hiding of room geometry, leaving just visible Imported geometry, statics and/or moveables