1.637 Update - twitch drops and other improvements

- Added the sofa and hobo barrel.

- Fixed the invisible roof bug. Conditional roofs still need more work, always more work.

- Half snap mode just has an on or off state now. Places the foundation up or down based on where the mouse is over the edge placement colliders.

- Improved steps and ramp placement. Easier to place when foundations are on each side.

- Foundation placement colliders are now spheres instead of boxes. This allowed for the above improvements and resolves some other issues.

- Timers can now be set with decimal times as low as .25 seconds.

- Pressure pads will send a power pulse when not powered.

- Fixed the copy-paste set center bug from the patch this week. If you have a save below the ground, use the move tool in edit mode.

- Fixed campfires being redblocked on floors.

- Fixed stability mode not showing info if parts were under 5 stability.