link: move from disabled to common

Author: pietroalbini

src/disabled/link.rs renamed to src/common/link.rs

@@ -45,7 +45,7 @@ pub use self::if_range::IfRange;
 pub use self::if_unmodified_since::IfUnmodifiedSince;
 //pub use self::last_event_id::LastEventId;
 pub use self::last_modified::LastModified;
-//pub use self::link::{Link, LinkValue, RelationType, MediaDesc};
+pub use self::link::{Link, LinkValue, RelationType, MediaDesc};
 pub use self::location::Location;
 pub use self::origin::Origin;
 pub use self::pragma::Pragma;
@@ -165,7 +165,7 @@ mod if_range;
 mod if_unmodified_since;
 //mod last_event_id;
 mod last_modified;
-//mod link;
+mod link;
 mod location;
 mod origin;
 mod pragma;