Hello world!

- Added level "Swings".
- Added "width" option to mechanic platform.
- Changed mechanic platform to act as semi-solid platform.
- Fixed crash which occurred when player tried to use Playlist Portals.
- Fixed problem, when loading and editing level during a multiplayer would erase its filename upon saving.
- Fixed a bug, where game would try and send listing request even if the tap wasn't ticked.
- Fixed an issue where players could easily insert multiple semi-solid blocks in a same space without noticing.
- Fixed background loading issues with Linux.
- Fixed an issue where laser could shoot through solid blocks.
- Fixed an issue where deleting elevator from under the player caused the game to crash.
- Force arrows and jumppads now throw player off from the lift.
- Improved elevators and (hopefully) got rid of getting clipped through them.
- Improved semi-solid block collision with players.
- Improved physics between mechanic platform and player.