update play-ground.html

[gordonwoodhull]

This has been neglected since Nov 2013. At a quick glance I notice the following problems:

• the choropleth is blank
• date barchart has brush drawn over the whole area, and it can't be resized or reset.
• brushing over the negative bar chart doesn't take - although this chart shows the new selection, the other charts rebound.
• it would better to use controlsUseVisibility so they don't jump around when controls appear.
• it seems to get into a loop and run continuously - from the start you can see the table being rebuilt a few times per second. transition.end spawns transitions? unclear. renderlets may be involved.
• after about 30 seconds it spews hundreds of logs about drawing infinitesimals. after a few interactions these appear forever.

In addition it has a jerky easing behavior which was probably always there - it goes most of the way to where it's going and then pauses for half a second before bubbles/bars disappear/grow to size. Maybe due to the large number of charts?

[gordonwoodhull]

The playground also seems to have lent some very specific and suspicious CSS to the larger project, like

.dc-chart g.county path {
    stroke: white;
    fill: none;
}

It looks like dc.css was originally an example in test/ and got promoted to the library itself in 22789a0

We should review which CSS refers to objects created by code - anything created by an example should not be in dc.css.

It can cause weird accidental problems: http://stackoverflow.com/questions/41139341/dc-js-choropleth-map-chart-css-conflicting-with-colouring-no-map-showing-how-c