CRM-15143 - adding postal_code for autocomplete and contact reference searches. Also correcting info in Upgrade/Incremental/sql/README.txt.

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* CRM-15143:
  https://issues.civicrm.org/jira/browse/CRM-15143
Merge pull request #3895 from davecivicrm/CRM-15143

CRM-15143 - adding postal_code for autocomplete and contact reference se...