Reduce firmware size by refactoring global data defined in public
headers.
Each global variable which require runtime initialization adds
initialization code to every translation unit which includes the header
where the variable is defined and declared.
Crush was caused when using std::to_string() on rt1051 to convert double (result from equation) to string.
Other methods f.e. using std::stringstream, sprintf also do not work.
Add own floating point converter to string.
Marcin Smoczyński