Setup for toggling to airport view.

This adds a method in the model to extract the airport data from the DB if it
exists. It assumes that the data is stored in the database as a json encoded
string. It also modifies the controller to include this information in the data
and the 2D view to display toggles between the views if the airport diagram
exists.
Add controls to toggle views.

I've added the javascript to toggle between airport and circular views. There
are still issues with highlighting nucleotides and the like, but this is a
start.
Update rna2d lib
Shrink width so we don't overlap in airport.

In an airport view the plot overlaps with the jmol window slightly. We shrink
the size of the view to prevent this.
Alter airport view plot height.

We need to shrink so the plot height to prevent distortion.
Calculate plot height on the fly.

No need for me to redo the calculation each time, just have the javascript do it
each time we use it.
Hardcode rna3dhub url.

This means we always uses a consistent and the correct format for the data
produced. I don't have the full pipeline working on my machine so the
interaction format may not be the same as on production for all structures. This
avoids this issue.
Hide and show jmol when toggling between views.

We hide and show jmol as we switch between views.
Show a disabled button when no airport exists.

This makes the page consistent for all structures. May add tooltips to make it
know that an airport exists for other structures.
Add tool tip to disabled button.

If we have no airport diagram we add a tooltip to indicate that.
Fix highlight nucleotides in airport view.

In an airport view we increase the size of nucleotides and color them red when
hovering and undo this when we stop hovering. This change does that. Previously
we always used pie.addLetters to draw a letter somewhere.
Decrease font size of airport view.

This makes everything look better in airport view with less overlap.
Mark long range interactions as dotted lines.

This makes it very clear which interactions are long range and does not force
the user to learn another button.
Add method to get all long range base pairs.

This will get all long range basepairs from the database, it returns an array
with nt1, nt2, family and crossing data.
Add crossing data to the page.

This json encodes the data and puts it in the page. In addition it adds some
help information about the crossing interactions which are displayed as dotted
lines.
Mark long range interactions as long range.

This merges the long range data into the interactions table and uses that
information to add a class to the interaction. This is how we mark interacitons
as long range in the drawing.
Update help modal.

This add some text about the airport view and long range interactions. In
addition it formats things a bit to make it more readable.
Display motifs in airport view.

This displays all motifs in the airport view. The motifs are taken from loop
download page Anton has provided. In addition we update the help
information, add controls for motifs and change Show Numbers to Show numbers.
Use production loop data.
Merge pull request #17 from BGSU-RNA/feature/2d-airport

Feature/2d airport