Support for Apple Pay and Google Pay added to POST /sessions method

To use walletPay

• paymentType must be either apple_pay or google_pay
• walletPayload is mandatory
• walletPayload must be the payload received from Google Pay or Apple Pay
• walletPayload must be base64 encoded

Header App-Version added for all methods

• Usage: key App-Version value ios-3.1.0-52
• Optional header
• Even though the format is not enforced, it is encouraged to send app version as [platform]-[version]-[buildNumber]
• Maximum length is 20

chargingStatus stopping added to GET /sessions response

When a stop request is received by the server and the stop request is being processed, the chargingStatus returned is stopping until the session state changes

stopping status is only returned for newer releases of the apps
(Apps that provide App-Version in the header of the API request)