Perl SDK initial contribution

This includes the initial version of the Perl SDK (v0.22) that's also available via CPAN.

What's included:
* Application and admin authentication
* Support for collections and entities (CRUD & queries)
* Creating, querying and deleting entity connections
* Bi-directional collection pagination
* Support for auto paging in collections

JIRA issue: https://issues.apache.org/jira/browse/USERGRID-151

Submitting under ICLA: Anuradha Weeraman