Actually handle a case where Amazon returns instance item in an ARRAY not only in HASH. 

This commit fixes two issues:
1. Amazon returns instance item in an ARRAY where this item is a cluster that has one or more AMI as a member.
2. the name is not being properly extracted from the tagSet.

Please note that this is my first actual perl code and I have doubts about using $_[1] in my function. You are more than welcome to comment/modify before merging. 

Thanks