Create download form

[bartaelterman]

Create a form to download data:

• [x] Start date
• [x] End date
• [ ] Download data button
• [ ] Calendar UI elements (optional)

[peterdesmet]

Blocked by #45

[peterdesmet]

I see two options:

1. Download links

Advantages:

• Good connection with current interface and selection mechanism
• Easy to implement

Disadvantages:

• Even though API supports it, user cannot download a custom range (but can do so offline on all data)

2. Download form

A form with two text boxes for start and end date + a download button

Advantages:

• User can select custom range

Disadvantages:

• More complex (i.e. date validation + potentially calendar UI to help user)
• No connection with what user is currently viewing (doesn't feel like it's part of the viz).

OK if I implement option 1?

[bartaelterman]

OK

[peterdesmet]

Option 1 implemented in 4349c8272cebc0282a4709555d0cd3dc5c0aa2a6, using d3 to update the href attribute of the download link on a new selection (so no on("click") event required).

I also subtracted one day from the year range, so instead of the previous 2010-09-01 to 2011-09-01, it now shows 2010-09-01 to 2011-08-31. This is more what the user expects (e.g. title shows sep-aug, instead of sep-sep and only unique dates are listed in the download): a30cf1d52fba3dc6bbfbec300b7e5bc022efbc34