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.

Note: https://github.com/civicrm/civicrm-core/pull/7479 needs to be applied for the fee to be correctly set.

FIx constraint violation if we try to insert 0 for campaign id.

https://github.com/drastik/com.drastikbydesign.stripe/issues/92

Check if there are no existing subscriptions before attempting cancelling

Support for cancelling recurring contributions.

Fix cancelling of an existing subscription

currentTotal is not defined on event registration pages.
TEMPORARY fix.

Minor tweak, check if form has payproc.  Remove Civi 4.4 from compatibility because I don't think recent changes are compatible.

Fix in civicrm_stripe.js that was causing "Stripe.js Not passed" because token was empty.
Fix error message about accessing static variable.
Large cleanup to code structure in stripe.php.

Refactoring to properly load stripe on submission error.
Better loading of stripe details in stripe.php.

See https://github.com/drastik/com.drastikbydesign.stripe/issues/76

- Fix for "Error: Stripe.js token was not passed! Report this message to the site administrator" on pressing confirm payment for event.
- Update for CiviCRM 4.6 changed selectors on determining current contribution amount.

Modify to stop error "Error: Stripe.js token was not passed! Report this message to the site administrator" on pressing confirm payment for event.

issue #76: Handle pay later in civi 4.6 (remove hidden_processor check).

Due to changes in CiviCRM you can no longer count on hidden_processor
field being present.

See https://issues.civicrm.org/jira/browse/CRM-15743