Removed the 'needsstorage' thing from Dsymbol. Arguments are not always given storage when applicable. This is not longer treat specially in this regard. Code for accessing nested variables and contexts rewritten. Probably more. Fairly well tested.

enum
{
    LLVMnone,
    LLVMintrinsic,
    LLVMno_typeinfo,
    LLVMno_moduleinfo,
    LLVMalloca,
    LLVMva_start,
    LLVMva_copy,
    LLVMva_end,
    LLVMva_arg
};