(Not major) Fixes broken Estimation Pane Tests

A HeadlessException is being thrown in Ant when constructing the Estimation pane. Setting headless to false allows the tests to be run in an environment that does not support Keyboard, mouse or display. As a result these two tests are failing in Jenkins.

Run tests in Ant, as tests will pass regardless in Eclipse. This is not a major pull request or fix, and can be done after we present.