Fix for db upgrade 4601 and others

possible fix for #155 - makes transactions

Change function name from stripe_civicrm_buildForm to buildForm now that it is in the Stripe payment class.

4.7 dev issue155 - combine with previous large commit.
Update Stripe PHP library to 4.3.0

Quote unquoted string literal class name for is_a check  #170

Change mysql_query to CRM_Core_DAO::executeQuery.

https://github.com/drastik/com.drastikbydesign.stripe/issues/164

Fix wrong currency in plan names #157

Don't submit if the back button is clicked

Same syntax error on 4.7

 Errors when donors repeat across multiple stripe accounts (for 4.7)

If there's no credit card field, don't attempt to get token (4.7)

 Multiple Stripe processor accounts cause IPN fail (change vs. 4.7)

Adjustment to checking for live/test mode

My installation was not processing the previous method of checking live/test mode correctly -- test mode would come back positive but live mode was empty instead of negative.

See also https://github.com/drastik/com.drastikbydesign.stripe/issues/26#issuecomment-203485309

Fixes #123, typo in Webhook.php.

Better other credits area in README.

Fix sending receipt for recurring contributions.
Add customer.subscription.deleted event Webhook response.
Add CANCELLING RECURRING CONTRIBUTIONS instructions to README.
Potential fix for currentTotal in civicrm_stripe.js.