Fixed issue with internal real representation, incorrect for non x86-32 architectures. Cleaned up CallExp::toElem, moved implementation to tocall.cpp providing a single procedure to call arbitrary D functions fairly easily.

enum
{
    LLVMnone,
    LLVMintrinsic,
    LLVMva_arg,
    LLVMva_start,
    LLVMva_intrinsic,
    LLVMnotypeinfo,
    LLVMalloca
};