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.

[Environment]

DFLAGS=-I%@P%/../tango -I%@P%/../tango/lib/common -L-L%@P%/../lib -version=Tango