Fix One Name Issue

Worked with @aaronrichmond to resolve the first name only bug where if a user only had one name defined in their Amazon account, the newly created Magento customer would have a blank first name and a last name equal to their first name without the first character (Matt would be 'att'). This logic will instead use the name value as the first name and use a period '.' for the last name to meet the magento requirement of having a last name. It will also prevent the redirect to the user profile during checkout that the user currently experiences.