Add Indexes for All Columns Storing Option Values

Tables with columns which are implicit Foreign Keys to civicrm_option_value records should contain an index on those columns. Please go through the xml schema files and add indexes.

EXAMPLE: Individual.xml -> gender_id column should be indexed

Some ideas for catching all these references...

• grep the xml files for instances of all the option_group names created by civicrm_data
• grep for CRM_Core_OptionGroup to see which object/forms reference it
• ??