Kill the whitespace
Add some basic helix coloring
Add code to color by helix

We can now color all nts by the helix they are part of. This will color the
helixes as well as the helix labels using the color for the helix label.
Remove some debug statements
Add highlighting to helix labels

Now mousing over a helix label can enable highlighting all letters in the
helix. This is done through the same mechanism as with all other mouseovers.
Right now the highlighting needs work as it is hard to read because letters
overlap. I also refactored how the mouseover and mouseout handlers are
generated.