Added next/prev metadata as data attributes of html element
Merge branch 'master' of github.com:suttacentral/suttacentral-data
Merge branch 'master' of github.com:suttacentral/suttacentral-data
Merge branch 'master' of github.com:suttacentral/suttacentral-data
Merge branch 'master' of github.com:suttacentral/suttacentral-data
Merge branch 'master' of github.com:suttacentral/suttacentral-data
Eliminated superfluous id in hgroups in older pali texts.
Merge branch 'master' of github.com:suttacentral/suttacentral-data