introduce tolerance on floating point numbers by using Test::Number::Del...

...ta::delta_ok instead of string equality

You remember my RT ticket https://rt.cpan.org/Ticket/Display.html?id=73963 ?

I've fixed the two broken tests by replacing Test::More::is() with Test::Number::Delta::delta_ok() and adding Test::Number::Delta to the prerequisites.

Hope you like it,

Best wishes,