Various minor frontend CSS tweaks
- Static border color for stats, teams list, map draw widget
- Explicit definition of table header
- New splitter design which works with the Qt style “Windows”
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.