Allow other columns to be defaults for scatter plot

[mccalluc]

From @thinkh: Caleydo/caleydo.github.io#161

• web_bundle version: 0.0.1
• browser version: Firefox 49.0.1
• OS: Windows 10

Reproducer:

http://phovea.caleydo.org/tutorials/frame.html?demo_getting_started/demo_4

Observed behavior:

Expected behavior:

A different default selection from the two drop downs that give a better impression, e.g. as follows:

Right now, to get a different set of axes you need to

1. Extend the options
2. Replace the default selectedIndex
3. Use the new options in the tutorial

... but it seems that this is something that should be easier to configure.

[sgratzl]

use https://github.com/datavisyn/phovea_vis_scatterplot/blob/master/src/index.ts#L36 instead

[mccalluc]

Can the existing scatterplot be removed? Can documentation refer to https://github.com/datavisyn/phovea_vis_scatterplot? How would a new user know that it exists, and is the best thing to use?

[sgratzl]

invalid: removed