Generalize stats from f64 to the Float trait
Use is_zero
Add Richo Healey to contributors
Lower armhf target feature to v6.
auto merge of #13961 : richo/rust/richo-author, r=alexcrichton

Shamelessly adds myself as a contributor.
auto merge of #13962 : luqmana/rust/al, r=alexcrichton
auto merge of #13822 : EdorianDark/rust/master, r=cmr

New attempt to generalize stats, after #12606.
Since #12355 did not get merged, i want go get first get my change done and the try to fix sum.