Merge pull request #121 from hlong290494/sbl-dev

Adds an export button that outputs selected requirements to a file.
Improve the extendability of SubmitPane.java by changing the buttons into array elements.

Reported-by: lhnguyendu
Signed-off by: Long Nguyen Duc <lhnguyenduc@wpi.edu>
Merge pull request #122 from hlong290494/cardButton

Change the card buttons into array elements
Add action listeners and parsing to button handling code.

CoAuthors: rbkillea, lhnguyenduc
Merge pull request #123 from cgwalker/sbl-dev

Add action listeners and parsing to button handling code.
Header: Make the team estimate data a Table.

Reported-by: lhnguyenduc, cgwaler, rbkillea