Improved subscribers list fetching

[andreibaca]

Optimise the subscribers method to use less queries to get all the contacts

[andreibaca]

So there was a bug when the subscribers number was exactly the same as range it would try to make another request that resulted in the exception: "Yet,There are no contacts in this list."
I could not find a solution but to change the way the function works. I don't understand why the unit test is failing - the method works live with zoho.

[cappuc]

Hi @andreibaca

I've made some changes to your code:

• I've removed the call to get the subscribers count because it's not necessary (we can't get all subscribers at once because it's limited to 650)
• I've added a try-catch to handle the "Yet,There are no contacts in this list." exception and just return in this case

Fix #24

[andreibaca]

I did not know about the 650 limit.
Then if the $range param was null it could have been set to 650 instead of unlimited in this case.