Fix saccade velocity sorting

[ashkjones]

Fixes #40

• Uses the fixation data to determine which AOI saccade data belongs to. (Slower than sorting using the AOI tag but ensures that the number of saccades used in the Saccade Velocity calc matches the total number from in the Saccades class.)
• The documentation word doc was updated with the changes. I also started adding javaDocs so I can get method descriptions on hover in my IDE. The javaDoc matches the method descriptions in the word doc.