Add validation of mandatory fields via JS.
Enforce mandatory fields server side.
merge from master
Fix mad merge from master.
Fix mad merge from master.
Fix mad merge from master.
Fix formatting.
Ensure other fields related to bibId are cleared if BibId is cleared plus some minor refactoring.

Note that title won't be overriden because on the server side, it is ignored if it is attempted to be set to blank.
Refactoring this class to remove some copy-paste duplicates (these were causing issues), generify things that are Node properties, move around some stuff to make it a little clearer.
Fix a jquery selector that was not selecting correctly.
Add validation support for paired fields.
Add pair validation for Record Source/Number
Change sensitiveMaterial to a lookup and fix todo.
Add validation of Record Source pairs.
Fix a bug where the bibId field dissapears if it's blanked.
merge from master
Merge pull request #612 from nla/bug/acm-dsc-508

Bug/acm dsc 508