CRM-15433 - Fix skipPayment function so it works regardless of currency localization.

----------------------------------------
* CRM-15433: Billing info and payment options blocks not hidden for $0 events with price sets when decimal delimiter is NOT a dot
  https://issues.civicrm.org/jira/browse/CRM-15433
Merge pull request #4421 from davecivicrm/CRM-15433

CRM-15433 - Fix skipPayment function so it works regardless of currency ...