v0.5.3

Primes v0.5.3

Diff since v0.5.2

Closed issues:

• Performance regression in isprimes (#46)
• Small mod for correct "factorization of products" (#58)

Merged pull requests:

• simpler and slightly faster factorization (#114) (@oscardssmith)
• WIP: increase speed of Factorization objects (#115) (@oscardssmith)
• switch PRIMES to MIN_FACTOR (#117) (@oscardssmith)
• Add eachfactor iterator (#118) (@oscardssmith)
• update version (#121) (@oscardssmith)