Added search bar and empty search script.

TODO: make the search actually work, style the search bar. I think I'll do the latter first, it's easier. :P
Added db-search.js
Moved get_header() to after the declaration of $mode.
Edited db-search.js to split search terms into words, separated by spaces.
Merge branch 'master' into db-search

Conflicts:
	database.php
	include/header.php
Re-added things removed in the merge.
Separated header code for DB and Discuss so that the search box is only added in the DB.
Put search box on the right, approximately centred vertically.
Add icon to search bar.
Fixed search JS.
Entries fade out/in instead of disappearing.
Search bar expands on focus.
Search bar JS is now executed when the document is loaded, and therefore works.
Closed .search-container div.
Search unfocuses on enter and when the search icon thing is clicked.
Added search match highlighting via a highlighting plugin by Bartek Szopka (https://bartaz.github.io/sandbox.js/jquery.highlight.html).
Added regexes for filters.
Regexes aren't global anymore.
Forbidden/required word regexes look ahead for \s instead of ending with \b.
Began work on author filter.