add "parent item" info for child notes from letters and interviews

[erazlogo]

this should be added for reports and also for the space on top of the note, which is currently empty for notes linked to letters and interviews. as a result, a reports on notes from letters looks like this, with no way to know which letter the note came from:
​http://digitalhistory.concordia.ca/uploaded/notesfromletters.html
instead, formatting could be something like this: ​http://digitalhistory.concordia.ca/uploaded/reports/notes.html

[erazlogo]

Dan--I forgot, we can't set "letter to X" or "interview by Y" as the title because that's not portable to other languages. It'll have to be just "Letter" or "Interview" which is the same as the item type label and then can be translated.

[dstillman]

It may be portable--we can use variables in localized strings, such as "Interview with %S". The only potential problem would be with multiple creators, but with a few different localizable strings (maybe for 1, 2 ("Interview with %S and %S"), and 3+ ("Interview with %S, %S, and %S") creators), it may be possible. Just let me know what the various strings should be.

[erazlogo]

Could you do this: for the part that goes into the title in the middle pane, it should be: for 1 recipient, "Letter to %S"; for two, "Letter to %S and %S"; for three, "Letter to %S, %S, and %S"; for more, "Letter to %S et al." The same with interviews, except you'd start with "Interview by ..." (Not "Interview with..." because the "interview with..." people would go into the creator column in the middle pane).

But for the report's "Parent Item: " (and in the "title" space on top of the note) without the author of the letter and the interviewee it will be hard to know which source the note is coming from. So you'd have to include the author info, something like the formatting in my example above (but if you can do "letter to..." then probably it should be formatted as "Stothard, Letter to Valee, 8 May 1928"). So it seems that there have to be two different cases--one for middle pane, another for reports, etc.

[dstillman]

(In [1748]) Addresses #756, add "parent item" info for child notes from letters and interviews

• Displays placeholder title in square braces for letters and interviews without titles
• Ignores square braces and quotation marks when sorting fields

[dstillman]

(In [1763]) Closes #756, add "parent item" info for child notes from letters and interviews

Also:

• Adds two modes to toArray() for including letter/interview titles
• Adds mode to getDisplayTitle() for including author and date