Eagerx-gui

Fix
* Use atexit to close apps and allow to save gui render to filename ([`259a567`](https://github.com/eager-dev/eagerx_gui/commit/259a567530740c2e792b32ab98e3434c9ec31879))

Fix
* Make compatible with pyqt5 and with colab render node ([`d05fc0b`](https://github.com/eager-dev/eagerx_gui/commit/d05fc0ba5fe42be51f160ee71a7b7fb1ab5bb097))

Fix
* Alphabetically order nodes and terminals in gui ([`7bfddce`](https://github.com/eager-dev/eagerx_gui/commit/7bfddcee0a7f0be6b88b0eb8f0e2acaf4ff7c5c2))

Fix
* Update gui because of refactoring in new eagerx version ([`bdda38c`](https://github.com/eager-dev/eagerx_gui/commit/bdda38c50b26aa0cc152e58826625f8fcec3e2f8))

Documentation
* Update readme because example was outdated with new changes ([`0187264`](https://github.com/eager-dev/eagerx_gui/commit/01872645377d2321e29e9eb7fd8709e3195ba433))

Fix
* Update dependencies ([`99e88d6`](https://github.com/eager-dev/eagerx_gui/commit/99e88d6f310044eba42a3ff01443ed24f4366833))
* Refactor bridge to engine ([`58fd2a2`](https://github.com/eager-dev/eagerx_gui/commit/58fd2a2c193771a589b91ccb59df0c1b82cbe791))

Fix
* Skip "spec" keyword, add "initial_obs" to SpaceConverter ([`166c4aa`](https://github.com/eager-dev/eagerx_gui/commit/166c4aa034db305516423169405d4de1bcdb88e2))