Fix #1719 "No content type output by persistence API for /form"
Minor: remove XML declaration
For #1716: Improve performance of FR Home page

- xf:delete action on ~3,000 nodes was taking a lot of time
- was due to normalizeTextNodes on each item
- don’t delete children elements, just replace root element
Scaxon: add elemValue/elemValueOpt
For #1716: FR Home page paging and faster join

- rewrote local/remote join in Scala to make it faster
- add pager and paging logic
- add oxf.fr.home.page-size property
Minor: use elemValue/elemValueOpt
Fix #1727: "Binary submission: no xforms-submit-error if reading fails"