Multiplane: descargar versiones anteriores

Two fixes contributed by @fisHarly0: copied job commands keep their encoder and raster settings, and a relative --root no longer splits one project into several on the Jobs page. Both the renderer and the desktop app changed; an npm release follows.
Renderer
- A relative --root no longer splits a project. Jobs started with a relative --root (for example --root .) stored that relative value in their events. The desktop app resolved it against each shot's own directory, so shots in shots/ and other/ showed up as two different projects. The root is now resolved against the working directory when the command starts and stored as an absolute path. Jobs recorded by earlier versions keep their current grouping, because the original working directory was not recorded. Fixes #3 (#5, thanks @fisHarly0).
Desktop app
- Copied commands keep encoder and raster settings. "Copy command" left out --encoder x264 and --raster gpu because they match the built-in defaults. If your saved preferences named a different encoder or raster mode, running the copied command used those instead. Copied commands now always include the raster mode, and the encoder for MP4 renders. Fixes #2 (#4, thanks @fisHarly0).