CSS Updates

Updated CSS around image links in image-placement boxes to be more aesthetically pleasing.

Added the ability to rename the TOOL_START_LINK to a custom value.

Signed-off-by: Seth Battis <SethBattis@stmarksschool.org>
Grading Turn-Around History

Completed Grading Turn-Around History section.

Signed-off-by: Seth Battis <SethBattis@stmarksschool.org>