Parse the NOT operator, the [idempotent] attribute, and the handle_t

Parse the NOT operator, the [idempotent] attribute, and the handle_t
and error_status_t types. Improved some parsing rules to get rid of
the LINK_LAST and LINK_SAFE macros. Enclose generated .h file within
an extern "C" (for C++). Output function prototypes for regular RPC
interfaces.  Fixed a couple of bugs.