Add "data" as a URL attribute
Improve tag handling API

Expose function tagsFieldWith and renderTagCloudWith to provide more
flexible tag rendering APIs; add tagCloudField and tagCloudFieldWith
to provide context-based facility for tag cloud rendering.
Merge remote-tracking branch 'upstream/master'
Fix indent
Merge pull request #134 from ian-ross/master

Add "data" as a URL attribute