* Don't validate CURL, MBOXFW, and NAPTR records as SPF records.
* Remove unnecessary comment about validating a record as SPF.
* Move validation for LOC records above the list of unvalidated records.
* Use htmlspecialchars when populating input values.
Merge remote-tracking branch 'upstream/pull/114' into reviewed (fixes #114)

Also add htmlspecialchars() to read-only dump of zone.

Conflicts:
	edit_record.php
add SPF content sanitizing to edit_record.php (same as edit.php and edit_zone_templ.php)
if pdnssec_command is set use it to rectify all zones - pdns needs this for all zones if dnssec is enabled