Detect and change all occurences where DB errors are not checked

[mattfullerton]

If a DB error results from a query, we should return an error in the request or cause an exception, e.g.

if (err) callback (err)

Instead of just carrying on regardless. Here's one suspicious occurrence:
https://github.com/NRGI/ResourceProjects.org/blob/master/server/controllers/source_tables.js#L83

Where in the logs we end up throwing an exception "Cannot read property 'company_established_source' of undefined" - it might be undefined because a DB error lead to no data being returned or might be undefined because there's a logic error in the code. In this particular instance there's also no check for whether the array has any objects before accessing item 0...

I would suggest searching for all occurrences of the term "function (err" in the controllers and checking them for error detection.