Fix lastGameType not being updated if game type was demo or save (fixes a crash) Previously, if you first played a normal game, then a demo, the “play again” button would appear, but clicking it would only crash HW. This fix will remove this button after a demo or save, because the frontend doesn't know how to restart demos or saves yet.

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.