Fixed ModuleInfo generation to no longer use the ModuleInfo class' default initializer for types/defaults, it's unsafe as initializers don't necesarily match the "formal" type. There might be explicit padding. Changed -g switch to emit DW_LANG_D debug info, make demangling work with a patched GDB, still more work to do for full support of D's Dwarf extensions. Added getNullValue helper method.

module multiarr3;

void main()
{
    static int[2][2] arr = [[1,2],[3,4]];
    assert(arr[0][0] == 1);
    assert(arr[0][1] == 2);
    assert(arr[1][0] == 3);
    assert(arr[1][1] == 4);
}