QTfrontend: Fix flickering and bad offset of control config popup If you opened the pop-up to change a key, there was a very short flicker at the left side and the pop-up had a bad offset which sometimes caused entries to be out of screen bounds.

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.