Add option to draw Info panel and the bottom and pin it

[st-pasha]

Currently it is only possible to access the information about a particular example through a small (i) icon in the top-right corner, which presents several challenges:

• the user may not be aware of this feature,
• navigating from one side of the screen to another is too much work (esp. if you want to read the description of every example),
• the info panel opens as an overlay, obscuring the example itself -- this means it is difficult to compare the text of the description with what is being actually rendered on the screen.

As a solution to these problems, I suggest a new option where the info panel would be rendered at the bottom part of the screen (the option could also allow to control how much of screen's estate to spend on that panel). The panel should also be "sticky": its visibility should not change when switching between examples.