Exclude backlinks from selection

Steps to test the change:
* Open a random page in browser.
* Select all or a part of the page.
* Copy the selection to clipboard.
* Open a word processor like LibreOffice Writer.
* Paste the content of the clipboard.

Change-Id: Ibae4292b5dd8cc02a769e85adfea991d8d6ceb59
Merge "Exclude backlinks from selection"