Closes #1565.

Report an error when creating entities with a non-existent model

Closes #1494

See merge request !1414

Closes #1494.

Fix crash when a moving custom entity activates a stream

Closes #1562

See merge request !1412

Closes #1562.

Initial pass of game:get_values implementation. It is working, with a test, but might need a bit more clean-up.

Move `config.h.in` template file away from include source tree

See merge request !1409

* This template file should not be inside the include source tree.
* The issue is that it gets installed into the include directory alongside
  the generated `config.h` file, which is incorrect behaviour.

removed forced GL version 46

See merge request !1407

Fixed Solarus Assertions

See merge request !1405

Improvements to Same Region Check

Closes #1425

See merge request !1381

re-enable Lua console and implement the toggle as a class attribute

See merge request !1402

update GLAD to latest version

See merge request !1404

fix building in MacOS after upgrade to C++17

See merge request !1403

fix date in changelog

See merge request !1406

* no significant code changes but lets keep up with upstream anyway

* the usage of `std::variant` requires a minimum deployment target of MacOS 10.14
* for correct compiler flags we must use `CMAKE_CXX_STANDARD` and related variables
* for C++17 support in the above variables, we need at least CMake 3.8

* there should be no need to comment/uncomment this block anymore

Changes to support Clang-cl and ANGLE backend

See merge request !1394

fixed bow crash

Closes #1550

See merge request !1401

Fixed map/game event ordering.

See merge request !1399

Restore joypad event args to integer for quests < 1.7

See merge request !1400

Camera smoothing + Dynamic Time-step

See merge request !1388