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 and should not be used to artificially modify the value. Multiply for fraction output should be 100 (fixed).