Merge pull request #841 from ArthurHoaro/feature/search-no-tag

Empty tag search will look for not tagged links

diff --cc application/LinkDB.php
Simple merge

diff --cc application/Utils.php
Simple merge

diff --cc index.php
Simple merge

diff --cc tests/LinkDBTest.php
Simple merge

diff --cc tests/api/controllers/GetLinksTest.php
Simple merge

diff --cc tests/api/controllers/InfoTest.php
Simple merge

diff --cc tests/utils/ReferenceLinkDB.php
Simple merge

diff --cc tpl/default/linklist.html
Simple merge