Changelog: Add 0.9.23 highlights, change headers, reorganize 0.9.23 engine updates, fix typos, mention some features
Lua scripts for engine testing. These scripts are the same as other Lua scripts
in Hedgewars, but you ought to call `EndLuaTest(TEST_SUCCESSFUL)` or
`EndLuaTest(TEST_FAILED)` when the test is completed.