Memory leak on iOS 9.3

Repeatedly calling `navigator.contacts.find` will leak memory up until the point the app is killed by the operating system. Instrumenting the call with Xcode will yield anywhere between 750 and 1000 new leaks every time it is called. The responsible frames are mostly `ABCMultiValueInsertAndCreateIdentifier`, and `ABCMultiValueCreate`. The responsible library is always `AddressBook`. This issue exists in version 2.1.0, but 2.0.1 is also affected. https://github.com/apache/cordova-plugin-contacts/pull/35/commits/d28ba9013cae21abc6826a1d6dbd06d841874c1d fixes it, but I believe it was never merged.