C++ mode in cise

[shirok]

We added cise macros for C++ new and delete, but that can break existing CiSE code that uses these words as identifiers.

It is easy to workaround by changing the existing code, but it's not desirable for the backward compatibility.

We can make CiSE aware of whether it is dealing with C or C++, so that we can switch handling of C++-specific words.

Choices:

• Just add a parameter to tell it's C++ mode or not. Easy, but somewhat ad-hocy.
• Since Global CiSE macros are stored in initial <cise-ambient>, we can provide multiple default ambients, one for C and one for C++. This has the advantage that we can easily add support of C-like languages (e.g. JavaScript) later.
• Name the macros specially, e.g. .new and .delete. We don't need the switch.