Use separate function for each header type.
Refactoring.
Added function that sets headers on feeds.
Added ``cache_max_age_seconds_for_search_results`` option.
Added support for feeds.
Added support for search results (initially no cache).
Improved comments.
Updated readme.
Set version to 1.0.3.
Added tag 1.0.3 for changeset 7996cceccafc
Fixed typo.
Improved readme.
Set version to 1.0.4.
Added tag 1.0.4 for changeset bacba4899998
Improved comment.
Tested up to: 3.8.1
Set version to 1.0.5 and updated changelog.
Added tag 1.0.5 for changeset 4c4b94bd0495
Tested up to WordPress 4.2.
Added plugin artwork.