Patch: addTo and Models.getModel renamed.

A few improvements:

• Models.getModel has been renamed to Models.get : a deprecation warning message will be displayed when using getModel
• Entities now have a addTo method, which allows Entities to be added to other entities. (Similar to .add, but with addTo the Entity is the child).

What's Changed

• created addTo for entities, renamed getModel to get by @marco-ponds in #178

Full Changelog: v3.17.5...v3.17.6