VRP improvements

Some improvements to the VRP visualization:

Tooltip for customers shows vehicle number.
Mousing over vehicle number in table makes that vehicle's route stand out from the others. (Helpful for distinguishing routes with similar colors)
Checking for duplicate, missing, or invalid customers in solution.
Strip whitespace from the end of lines to prevent the error mentioned in forums where the script fails silently due to an extra space.

Also changed the script tag to point directly to d3js.org instead of getting redirected there from github, which sometimes caused slow loading.

Finally, I increased the tolerance in the error-checking code for the FLP objective value to .01, since for some of the larger problems Python only gives two decimal places.