Merge pull request #24 from jvish/review

Review
finally got lines to light up on highlight
Carousel selection is working
add Windows shortcut files to the ignore list
Implemented an image viewer using carousel and image widgets

This is probably a common enough configuration that it will be worth creating an ImageViewer widget to encapsulate it, but I wanted to prove it could be done with the existing widgets.
Merge pull request #25 from mlippert/widget-refactor

carousel widget and demo of image viewer
beginning test files for assessment types.
lame quickie text bits in sketches. They don't preserve svg-compliant formatting at the moment, so I can't do sub/superscripts yet.
New widget imageviewer
Merge pull request #26 from mlippert/widget-refactor

New widget imageviewer
restoring vector functionality and length-angle spec for lines, rather than endpoint