Prevent entering “/”, “\” and “:” in team and scheme names. The name of teams and schems is saved in the file name itself, so these characters would cause trouble as they are used in path names in Linux and 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.