Fixed typo
Added ``validate_hostname`` utility function.
Implemented NS record validation.
Improved SOA record validation.
Improved hostname validator to reject hostnames with a trailing dot.
Implemented MX record validation.
Implemented SRV record validation.
Implemented A record validation.
Implemented AAAA record validation.
Implemented CNAME record validation.
Implemented PTR record validation.
Implemented TXT record validation.
Implemented SPF record validation.
Added slash to the valid characters in the 'export_zone' url pattern.
Added custom model form for the Domain model. Basic input validation has been implemented.
Added experimental support for zone cloning.
Fixed small bug with SRV record in zone cloning action.
User is redirected to the cloned zone's change form after the 'clone zone' action has completed cloning.
Cleaned-up cloning action.
Also clone the Dynamic Zone setting.