alexcrawford0927/cyclonetracking: v13.2

The main updates from version 12.4 to 13.2 involve the outputs up the main data frame in the cyclonetrack objects. Namely,

1. Changed u and v variables to be velocity instead of speed.
2. Removed Dx and Dy.
3. Changed sorting of main data frame to no longer always be alphabetical.
4. Added the SLP gradient measure (p_grad) used to limit cyclone detection as a variable.
5. Replaced all "longs" with "lons" when referring to longitude, making it the same number of characters as "lats" for latitude.
6. The dist2lon function was changed so that if the input is negative, the output will be negative. (It previously gave an absolute value).
7. Added a try/except statement to cTrack2sTrack function so that it will ignore cases where tids between two months don't align instead of breaking. Such cases lead to there being two separate system tracks despite a regenesis event being detected. This is a fringe case that probably effects fewer than one in 100,000 tracks.