Fundamental, tokenizing macros for complex preprocessor expressions.

There are several ways to handle parentheses, commas, empty and non empty
tokens that can be used as building blocks for complex expressions at the
preprocessor level, macros in the <odreex/ppmpf/prse.hh> offer the basic
blocks for something like this. Added PPMPF_PRSE_IZER, PPMPF_PRSE_IUNT,
PPMPF_PRSE_IPRN, PPMPF_PRSE_IPRT, PPMPF_PRSE_ITOK.