v0.9.1

Modia3D v0.9.1

Diff since v0.9.0

• Require ModiaLang 0.11.3 (avoids unnecessary double instantiation of Modia3D models).
• Reduce memory allocation of force elements.
• Update docu for contact force law (docs/src/internal/ContactForceLaw.md).

Merged pull requests:

• reduce alloc in force addition (#99) (@AndreaNeumayr)
• Improve docu for contact force law (#100) (@MartinOtter)