Add interactive postcode lookup and reverse lookup features

[giacecco]

This feature was so obvious I've always forgot to write it down. I apologise.

Add to the (gh-pages) website interactive postcode lookup and reverse lookup features.

• Lookup: one writes any part of an address and gets a list of full addresses OA knows of, matching that search string including their postcode. Require a minimum length for the search string (e.g. what's the shortest town name or street name we have in the reference tables?)
• Reverse lookup, one writes at least a postcode sector (all but the last two characters) and gets all addresses we know at the postcodes that match the search string. Manage loose formatting (spaces everywhere, lowercases vs uppercases etc.).

Clicking on any of the results takes you to the address human readable page.

I guess this issue upgrades from 1 to 2 points if we do what is described below, too

Ideally, this should be implemented to be portable to third parties websites as an example of using the publishing APIs, e.g. it could be implemented as two simple IFRAMEs plus pure client-side JavaScript implementation, distributed through a GitHub repository of its own.

This ease of portability implies adding JSONP support to the publishing APIs #458, though. If there is no time, leave JSONP for later and implement fetching the data directly (website and publishing APIs share the second level domain, so we shouldn't have cross-site scripting, correct?).

As a plus, the top results are displayed as the user writes, as a drop down list under the search textbox

[Floppy]

Are you aware we have simple search functionality on the alpha site? Or is the fact that it's embedded in another site and using the APIs a core part of this requirement?

[Floppy]

Removed points for now, that's to decide when we think about the cost of implementation.

[giacecco]

The first part of this will be likely recovered in sprint #38 , to be discuss at the sprint planning this afternoon. The second part will be packaged as a feature in Beta.

[giacecco]

I understand @floppy and @pezholio prefer achieving the same by moving the website away from gh-pages instead. This was already planned in #439 but postponed to gain time to tackle the latest sprint's issues.

It's fine for me but it needs to take place ASAP, in time for the Alpha pre-holidays soft-launch. Otherwise we need the client-side integration described in the first part of this issue. Please get back to me with your proposal / let's talk at the first opportunity.

[Floppy]

I'd suggest we re-open #439 and do that.

[Floppy]

Replaced with #439, so moving this to done.