For #1352: don't show legend border within th
Minor: indent
Remove unneeded resource-ref in web.xml
Remove unneeded isCustomInstance
Fix #1510 "Changing itemset value modifies label in all languages"

- rewrite read/write logic
- make dialog a bit wider
- some refactoring of the dialog
- restore local language selector (was gone in 4.0)
- fix appearance of hidden alerts
- use xforms-hidden instead of xforms-disabled to hide controls, as XForms engine can remove xforms-disabled