Add scrollable columns

[ddipanfilo]

[sourcelevel-bot]

Hello, @ddipanfilo! This is your first Pull Request that will be reviewed by Ebert, an automatic Code Review service. It will leave comments on this diff with potential issues and style violations found in the code as you push new commits. You can also see all the issues found on this Pull Request on its review page. Please check our documentation for more information.

[coveralls]

Coverage remained the same at 92.784% when pulling 92a79dd on make_idea_lists_scrollable into f5ede30 on master.

[coveralls]

Coverage remained the same at 92.784% when pulling 876676b on make_idea_lists_scrollable into ead21fa on master.

[vanderhoop]

hey @ddipanfilo, @crq, and @samdec11. the css changed the way PhantomJS saw the visibility of the lists, so i updated the end-to-end tests to look for the inclusion (or lack thereof) of the <li>s in question, and the build passes consistently. mergin!