Clean up macros

[stefano-zanotti-88]

This changes some NANOPRINTF macros to NPF, so that now a macro is a user-customizable option iff it is a NANOPRINTF one, whereas all the NPF ones are for private use (or guards). Of course, functions/types/etc. are still prefixed with npf.

[stefano-zanotti-88]

The presubmit checks fail because the tests still rely on the original macros.
Let me know if you like this change, and I'll fix them (but, can I commit changes in paland.cc?)

[charlesnicholson]

I think in overhauling the testing infrastructure, I will rewrite the paland tests without copying them, so all of this will live in one repo without having to tiptoe around the incompatible licenses. This is a good PR, thanks for doing it; I'll copy it over into a new PR that I do and link to this one, so that I can do the paland fixup.

[charlesnicholson]

Implemented in #339

[stefano-zanotti-88]

Regarding paland, maybe you want to rewrite a similar test suite, or maybe you might use some or all of the "exhaustive testing" and/or "fuzz testing" I've proposed here: #343.
Note that "exhaustive" means testing all possible combinations of specifiers/options, so as to catch edge cases, but it does not mean checking other things that are more important -- like using multiple specifiers in the same call, or various cases of float precision, or cases that are known to be tricky for proper rounding, etc.
So, a lot of hand-crafted tests are still needed.
Having all these interesting cases combined with all possible combinations of options would be infeasible -- there could easily be billions of test cases.