Broken links 1.7

Broken links v1.7 changes:

Fixed incorrectly named variable in the PHP code.

Broken links v1.6 changes:

Fixed null condition error.

Broken links v1.5 changes:

Added 'Broken links' to visitor menu.

Broken links v1.4 changes:

Now using finder for performing database queries.

Broken links v1.3 changes:

Added additional check to avoid server error log under certain conditions.

Broken links v1.2 changes:

Added code to remove 4-byte unicode characters.

Broken links v1.1 changes:

Added code to remove unicode from data fields.