New settings in game configurations

General settings:

int basegame - indicates which game the current configuration is based on. Used to load game-specific GLDEFS lumps (DOOMDEFS, HTICDEFS, HEXNDEFS or STRFDEFS)
Possible values: 1 (DOOM), 2 (HERETIC), 3 (HEXEN) or 4 (STRIFE).
Example: basegame = 2;

bool enabledbydefault - this game configuration is available by default.
Default value is "false".

Linedef definitions:

bool requiresactivation - this linedef action requires activation flag(s). When this property is set to true, a warning will be shown when a user selects this linedef action and no activation flags are set.
Default value is "true".
Example:
1
{
    title = "Polyobj Start Line";
    requiresactivation = false;
}

Thing and linedef definitions:

int default - sets default value for a Thing or Linedef argument definition.
Example:
9038
{
    title = "ColorSetter";
    arg0
    {
        title = "Red";
        default = 255;
    }
}