Search exact work
* #2971
search_exact - return empty array when there's no match
* #2971
Adding tests for search_exact
* #2971
Rewrite search_exact for clarity
remove some old code
Fix linking objects on search pages
* wasn't creating link when there was no taxonomy associated with the page
* #2976
remove duplicate span
Add rest tests for linking in search result description
Don't pass  into search when you don't need it
Move config into API so Xapian doesn't need  passed every time
Update search_exact
* betters args
* more useful return info
Update search_exact tests
Refactor Xapian Search
* Consolidated a few methods
* search, autocomplete, fetch, count_estimate, random -- main methods in Xapian now
Make xapian->fetch more consistent
Didn't update all of nucleotide aligner - new xapian fetch
search_exact -> _search_exact
* demote to helper method
Add comments, move things around
Fix bug
Fix disease fetch bug
Search through aceclass in xapian