SearchWP 4.4.0

[New] Extensions admin page to install, activate and deactivate SearchWP extensions in one click
[Improvement] Performance improvement when getting engines configuration
[Fix] Search terms highlighting doesn\'t work well with quoted searches
[Fix] Posts are not dropped from the index when a taxonomy term is deleted from the site
[Fix] Stemming prevents partial matches in some cases
[Fix] Search terms highlighting give unexpected results with partial matches

- **[Fix]** Edited document content is not preserved
- **[Fix]** Broken URLs for the redirects to the legacy admin settings
- **[Fix]** Class prefixing error in smalot/pdfparser lib
- **[Fix]** PHP7 static code analyzer error in symfony/polyfill-mbstring lib

- **[Change]** Plugin settings moved to the top-level menu
- **[Fix]** Undefined function error during the 'index' CLI command execution
- **[Fix]** Merging words in some cases during HTML content tokenization