Created UI "X" button that allows user to close tabs when clicked.
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Added a fix for being able to report GitHub  issues within Light Table. One can click the GitHub button on
the welcome page or select "Report an Issue" from within the Help menu.
Reverted files back to originals from Light Table master repo; I only want this (my personal branch)
to address the use "X" icon to close issue.
Merge pull request #1270 from mortontw/master

Close Tabs Using "X" Icon