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Issue #2147573 by drunken monkey: Improved error handling.
Issue #1773440 by drunken monkey: Added performance improvement for “filter only” queries.
Issue #2146749 by drunken monkey: Added soft commits as the default for Solr 4.
Issue #2099559 by drunken monkey: Made optimizing the Solr server optional.
Issue #2152337 by drunken monkey: Removed confusing "multiple text fields" section from README.txt.
Issue #1776534 by drunken monkey, e2thex: Added support for using a Solr server with multiple sites.
Issue #2151719 by Derimagia, drunken monkey: Added an alter hook for multi-index search results.
Issue #2222037 by drunken monkey: Fixed "Files" tab in Solr 4.7.
Issue #2175829 by danquah, drunken monkey: Fixed error when admin interface is not accessible.
Issue #2162627 by drunken monkey: Removed Solr 1.4 support.
Issue #2216895 by das-peter: Added support for empty/non-empty conditions on location field types.
Removed superfluous @todo.
Adapted CHANGELOG.txt to release 1.5.
Merge tag '7.x-1.5' of git://drupalcode.org/project/search_api_solr