Add div to display information in.

Whenver we click on something it would be useful to display information about
what we have clicked on. This div will serve as the place to do that.
Add info when clicking on nts or interactions.

This will display information about the nucleotide or interaction that has been
clicked. For interactions it tells what kind of interaction and provides links
to the nts involved. For a nt it provides a link to that nt page.
Open nt links in a new window.
Hide about info when selecting.
Refactor showing the about box.

Move the code to show it into a simple function.
Clean up display of jmol controls.
Make about a block message.
Use correct id to show in stereo.
Revert to checkbox for nt numbers.

Currently we have to use a checkbox for showing the numbers. Maybe in the future
this can become a button as well.
Keep both changes
Minor tweaks
Merge pull request #15 from BGSU-RNA/feature/2d-info

Feature/2d info