Adopt actively mantained fork of printf submodule

[ricted98]

I have noticed that the current submodule of printf points to a repository which is no longer mantained (see mpaland/printf#128). Instead, a fork of it is currently the most up-to-date version available (see https://github.com/eyalroz/printf). Since I needed some specific format specifiers to run selected benchmarks of Cheshire which were better supported in the currently mantained fork, I went through the changes needed to switch to the new submodule.

Some observations:

• The new submodule requires an additional compilation define (PRINTF_ALIAS_STANDARD_FUNCTION_NAMES_HARD)
• The header to be included is now printf/printf.h
• Several format specifiers resulted in warnings due to data types mismatches. I should have fixed them.

If you believe it makes sense to adopt it generally, we can iterate on this PR.