- use allocator class to wrap the stream pointers instead of passing
them into ISstream, OSstream and using a dynamic cast to delete
then. This is especially important if we will have a bidirectional
stream (can't delete twice!).
STYLE:
- file stream constructors with std::string (C++11)
- for rewind, explicit about in|out direction. This is not currently
important, but avoids surprises with any future bidirectional access.
- combined string streams in StringStream.H header.
Similar to <sstream> include that has both input and output string
streams.
