Modify src/gmp/z.d

Fix dub test

*** empty log message ***

Merge remote-tracking branch 'origin/master'

Correct return type of `isDefinitelyPrime` to `true`

Remove src/gmp/traits.d

Deduce loop range from samplePrimes in unittest

Remove scope from swap()

Modify dub.sdl

Modify dub.sdl, src/gmp/q.d, src/gmp/z.d