Fixed: "Sectors -> Select Things in Selected Sectors" menu item was not...

Fixed: "Sectors -> Select Things in Selected Sectors" menu item was not triggering the appropriate action.
Fixed: "Select Things in Selected Sectors" action was clearing selected sectors without updating the display.
Changed, Sectors mode: number of selected things is now displayed in the info panel.
Changed, Game Configurations window, "Testing" tab: game engine executable browser now opens up when clicking the "Add game engine" button.
Changed, Game Configurations window, "Testing" tab: default game engine display name is now generated from the folder name game engine executable is in.
Changed, Visual mode: Sector_Outside (87) sector effect is now taken into account when determining sector fog color.
Game configurations: added "defaultwalltexture", "defaultfloortexture" and "defaultceilingtexture" parameters. These define textures used when drawing a sector (usually the first sector of a map only).
Game configurations: classic game configurations now use "-warp" command to load the map.
Game configurations: factorized testing parameters into "Includes\Test_params.cfg".
Added internal functions to Hexen acs scripting configuration.
Updated documentation ("Game Configuration - Basic Settings" topic).