"distributed" multiplication in deg2hms to avoid rounding error due to floating point rounding errors.

[AstroTeutloff]

I've just edited the one line in the function, it could be that the deg2dms function has the same issue.
Minimal working example is now:

use flare::spatial;
fn main() {
    let hms = spatial::deg2hms(180.5);
    println!("{}", hms);
    assert_eq!(hms, "12:02:00.0000");