Added exact-integer? and expt-mod
Added math.prime
Documenting math.prime
Error message fix
Added (.type typename) cise expression

Sometimes we need this, for rendering typenames differ from
rendering values, and there are cases that we can't infer
which (e.g. argument of sizeof, which can take typename and
value.)
Added multi-copy operation in gauche.uvector

Covers the common operations such as copying same contents
repeatedly, or scatter comact data into sparse data and vice
versa.
Speed up prime generator using multi-copy! operation.
Added factorization and a couple of fixes in math.prime
Actually we can memoize primes as well in naive-factorize
Exposed small-prime? from math.prime
Added jacobi symbol calculation to math.prime
Added twos-exponent and power-of-two?

Also revised some code in math.prime.
Code cleanup
Comment fix
Added bpsw-prime?
Improved mc-factorize
Added totient, fixed factorization code
Changed default params in miller-rabin-prime?

Repeating 7 times makes it slightly faster than bpsw-prime?.
(The previous default) 20 is overkill---it's not only slower
than bpsw-prime? but also that it is known that Miller-Rabin
is deterministic below 2^64 if all prime bases <= 37 (first 12
primes) are used.
Further fix in miller-rabin-prime?

Guarantee that randomly selected base >= 2.
Document fix