Add a freq/distribution of ibtracs hurrs to analysis.

Interesting, shows that it's OK to use June 1st to Dec 1st (although it
will miss some hurricanes). A plot similar to the ones it produces can
be used when talking about ibtracs data source.
Add tracking analysis plot that can plot different pls/scales against eachother

Shows consistently that scale 3 is better. Little differences between
995/850 (both have 5 'wins' on avgdistovermatches), although 995 is
better on WLD: 6 to 2.