Custom Waypoints

* Added looping figure animations: pulse, grow, spin, bob, height, wave, ripple, breathe, flicker and rainbow, each with its own time and amount
* Added figure gradients, edited on a gradient bar: the colors run along the fade
* Added a border slider for figures
* Figures can now use glitch_in and glitch_out in the editor
* Added an in-world gizmo to the editor: arrows to move on an axis, a square to move freely, rings to turn and tilt, a size knob and width handles with stretch on (Ctrl snaps)
* Right click over the world turns the camera while the editor is open, and F5 changes the camera view
* Ctrl+S saves in the editor
* Added one background per line, each with its own color, opacity, size and style, plus a line spacing slider
* Added /waypoint copy and /waypoint paste with the {(...)(...)} format, also used by the editor bottom bar
* Added /waypoint animate, /waypoint gradient and /waypoint background multiline
* New waypoints are created with far_front render
* Added Set to everyone: with the plugin, an operator edits the server waypoints from the editor
* Added an API for other mods: waypoint and figure builders, paste and copy, enter and leave events, and figure shapes of your own
* The fade of text figures is now continuous instead of stacked layers