Fix currency output for fraction values.

Fixes #1329: https://cakephp.lighthouseapp.com/projects/42648/tickets/1329-numberhelpers-currency-method-ouputs-wrong-numbers-when-places3-and-number-between-1-and-1

The places are for decimal places (as documented: "Number of decimal places to use") and should not be used to artificially modify the fraction value. Multiply for fraction output should be 100 (fixed) as default, but adjustable via some option (as there are many different used formats here).