refactor search history logic so we're pulling search query parameters out of the database, not the session.
refactor previous/next docs to use only a single extra solr query.
pass around the current search id when linking to documents
raise poltergeist timeout under jruby.
move search history window into the blacklight_config.
split the search context controller methods into a separate module.
bump the default SearchHistoryWindow to 100
add search_context parameter to allow the full search context params to get passed in
require that the search-to-be-saved is in the user's search history.