0.3.2

Changes:
- Links where the endpoint is left of the start point and on the same height now have
  a slight vertical component in their curve so they don't appear as a single line
- Links now use a gray instead of black color for better constrast

Fixes:
- Build scripts now use bash instead of sh, as they were already using bash features before,
  which could lead to problems where sh is not a symlink to bash

Also, from now on, releases will have a source tarball with vendored cargo dependencies attached, so that releases can be built offline easier.

Helvum is now built via meson, which will install new icons and a new .desktop
file in addition to the binary.

The plain cargo build still works (for now), but will not install the additional resources.
In the future, a plain cargo build may become unsupported.

Changes:
- Add meson as new primary buildsystem.
- Add application icon and symbolic icon
- Add .desktop file